This is my rough translation of the DKW F89L and P engine and four speed gearbox repair instructions from the 1952 DKW Praxis magazine volume 5. My German isn't particularly good so these instructions may contain translation errors. The original German article can be found here: https://dkwautounionproject.blogspot.com/2019/08/1952-dkw-praxis-vol-5.html
On the first pages of our DKW practice we introduced you to the new DKW Schnellaster ¾ tonner. We can very well imagine how the DKW workshop men will have itchy fingers to get under the hood as quickly as possible to see what it actually looks like underneath. And here it is, the engine with the new gearbox.
The 700 cc Two Cylinder Two Stroke with Four Speed transmission
As you can see from the picture, the external dimensions of the unit with four-speed transmission does not differ too much from the previous three-speed unit. Compared to the dry weight of the three-speed unit of 105 kg, the new one weighs 112.5 kg. Some of you will immediately ask how many new special tools are necessary in order to be able to handle the new unit - to get straight to the point, some special tools are necessary, but not that many, so every workshop that deals with the maintenance of the DKW Schnellaster can be ready in a short time. These special tools are currently being developed and we will provide you with their order numbers and describe their use in detail in the next issue.
What does the engine and especially the four-speed gearbox look like inside? You can see it from the two sectional drawings below. The engine itself, i.e., the cylinder, cylinder head and crankshaft, have remained the same and is therefore well known to you.
However, the mating surface between the crank and bell drive housing has been changed, so we have developed a new crank housing to accommodate. Nevertheless, the crankshaft bearing tools can be used in the usual way and nothing needs to be changed on the engine jig.
So, we can limit ourselves here to an explanation of the gearbox and the clutch. Virtually the same steps are necessary for installation and removal as before. Pay particular attention to the front and rear engine mountings (see also picture on page 22). These motor mountings limit the movement of the motor in operation and the bolts should be tightened enough so that the motor can work freely. The flanging of the four-speed gearbox from the engine no longer happens in the usual way. This arrangement has become a little more complex and we want to try to explain it clearly with the help of the following sketches.
Before draining off the gear lubricant (which is no longer a special grease-oil mixture, but 2 litres of normal gear oil SAE 90), the clutch cover is removed via the locking screw on the bottom of the housing. The new F & S K 10 single-disk dry clutch immediately catches your eye. You can see the triplex chain and the drive sprocket on the crankshaft through a cut-out in the intermediate housing. Now loosen the 6 retaining screws of the clutch pressure plate (use the clamps supplied.) The plate is removed with the entire lever mechanism. The drive plate with torsion damping can now be easily removed. Next, the fastening nut for the drive pinion is loosened (a new holding device is required to counter-hold).
With the pressure piece no. 0 100 0160 screwed onto the crankshaft journal, puller no. 0968 is screwed on and the pinion pressed off. We will lengthen this puller a little so that it protrudes a little from the housing when it is applied and can be pulled out more easily. Now the whole clutch housing including the clutch bell, chain, large and small chain wheel can be removed from the front.
The large chain sprocket can be removed to the rear of the housing when the locknut and lock washer are removed. If it is necessary to remove the clutch bell, remove the circlip and press the bell with the hub out of the housing. The sectional drawing of the gearbox explains this better than words.
Now we can move on to separating the engine and transmission. This is done in the usual way by loosening the 5 retaining nuts on the bolts. It is advisable to unscrew the stud bolts that are used to fasten the intermediate housing beforehand, otherwise there is a risk that they will break out of the aluminum housing when the gear unit is installed. In the new engine, the chain tension can still be regulated by adding paper seals.
Now we're going to disassemble the gearbox as follows: first remove the inner joint on the clutch side. There are two types of joints that can be used - our well-known rubber joint in a reinforced design or a new metal joint (universal joint).
You don't need any new tools to remove the rubber joint; the tools are known. However, after loosening the retaining nut for the inner driver, you will notice that there is no longer a pull-off thread. The inner driver no longer sits on a wedge, but on a so-called polygon profile so that it can simply be pulled off at the front. Should be the profile be a little tight or stuck for a long time, you should be able to insert two of the tensioning screws for the rubber joints (do not screw into the sheet metal cap of the joint) so that they come to rest on the differential flange, thus pressing the inner driver off the polygonal profile. The metal joint looks like the picture on the next page shows. The 4 screws in the outer driver are loosened after the safety wire has been separated (alternatively, you can also use spring washers) so that the front part of the joint can be removed. Please make sure that when removing the front part, the needles in the log brackets do not fall out and get lost. Put the joints back together temporarily after removing them, otherwise there will be trouble. To loosen the spherical collar nut, you need a counter-holder that reaches over the inner driver. The inner driver can be pressed down with a standard two-bowl puller. Now the housing screws are loosened in the familiar manner. They are arranged in much the same way as they used to be, only stronger.
The speedometer housing is now loosened. The nut for the speedometer drive can be unscrewed when two gears are engaged. Now we take the helical gear and the washer above. The picture below shows the arrangement of the parts clearly. Then the circlip on the inside of the countershaft below is removed. Please ensure that pliers for inner and outer circlips are available and in a usable condition. They are often required in this gearbox. Now you can separate the two halves of the housing. Two extractors are being prepared for this work, which will effortlessly separate the halves.
Now the left half of the gearbox housing (seen in the direction of travel on the right) with a number of gears and the shifter parts in front of us. Further expansion is only possible when we have lifted the locking plate with tool no. 0928 and removed the shift rods. Starting with the shift rod for the 3rd and 4th gear and carefully knock it out from the clutch side. The shift fork remains on the shifter rod and the sliding sleeve can be removed.
Now we knock out the shift rod for the reverse gear. The middle shift rod (1st and 2nd gear) is knocked out last. With these shift rods, the shift fork remains in the housing. (Be careful of the detent spring and ball.)
To allow the fork for 1st and 2nd gear to be removed, the 2nd gear must be switched on.
The built-in spacer rings must not be confused with one another during reassembly, as otherwise proper switching is not possible. Also, be careful not to mix up the rods when you reinstall them. The picture on the next page provides information about their placement. Now the circlip in front of the driving sleeve is removed from the main shaft and the driving sleeve and 3rd gear wheel are pulled off. Now the circlip is removed in front of the clutch-side ball bearing and the head ?? out the directional and retaining washer differential for ball bearings. And the return bolt and knocks the return bolt in towards the clutch side. The return wheel can now also be removed. The countershaft is also removed by releasing the circlip on the clutch side and the disc behind it by knocking out in the direction of the differential. If you have to remove ball bearings from the housing and reinstall them, then warm the housing around the bearing seat to around 60 ° when installing. When removing the ball bearing for the countershaft, do not confuse the circlips.
And now we turn to the right half of the housing (left in the direction of travel). If the differential is not being repaired or replaced, it is not advisable to remove this unnecessarily. If it must be, it is only possible in the following ways: Take the joint that has not yet been removed and remove the differential flange. Then loosen the locking plates and the nuts of the 8 retaining screws of the differential carrier. You can now separate the ring gear from the differential housing by lightly fitting a metal bolt. The differential cage can be pushed out by placing a puller on the flange surface. When doing this work proceed carefully so that you do not damage the housing web with the gear rim. When the differential carrier is removed, the ring gear can also be easily removed. All ball bearings still in the gearbox housing are now knocked out or pulled off the shafts.
You can see from the foregoing that there is a whole lot more tasks to be observed than before (with the three-speed gearbox). For small workshops that do not have the appropriate tools and staff, it might be advisable to send the gear unit to us until you have had time to become familiar with handling them through workshops and other instruction.
The reassembly is to be carried out as follows:
During all work relating to the assembly, absolute cleanliness must be ensured, and the fitting areas and bearing seats must be freed from any adhering dirt particles.
The ring gear is placed on the differential housing and screwed into place.
Now we insert the complete differential into the left half of the gearbox housing (on the right as seen in the direction of travel) and hammer in the ball bearing 00625-040-40 with a sleeve that is in progress from the other side. After driving in, the differential must not rub against the gear housing; the ball bearing must therefore be driven in so far that it is still exactly aligned with the differential flange in the housing when the shim was placed. Now we hammer in the ball bearing 00625-031-40 for the countershaft from the differential side, also with a drive-in sleeve. Drive this bearing further into the bearing seat than necessary so that it stays straight in the housing. This makes assembly easier for you, because when assembling you must make sure that the wheels of 4th gear mesh correctly. Now we pull the ball bearing 00625-027-40 onto the 4th gear, thread both together slightly into the gear housing and insert the drive wheel for the differential from the other side so that it is on the one hand in the spline of the shaft and on the other hand in the gear rim that the differential fits into it. In front of the drive wheel for the differential, the spacer sleeve and the bearing 00625-039-40 are now attached and the bearing is knocked into the housing until it rests against the circlip that sits on the bearing. Now the 4th gear can be driven through from the inside to the back. If necessary, the ball bearing 0625-039-40 must be looked at again.
Now we take the other half of the gearbox housing and insert the inner circlip for the clutch-side bearing of the countershaft, then the bearing itself and the bearing for the main shaft 00625-039-40 with the circlip. We are not yet using the outer circlip for the bearing to the countershaft. Then we press in the countershaft from the inside. Here we support the bearing on the inner ring. Then we insert the return wheel into the housing and press the return pin into the housing from the coupling side. It is useful if the return wheel rests against the bearing block cast in the housing.
Now the circlip is placed on the main shaft in front of the clutch-side bearing. Do not confuse the two circlips on the main shaft. On the clutch side sits the one with the Zocken, on the differential side the smooth Seeger ring. Now the retaining washer for the ball bearing and return bolt is screwed on. This disc is not the same length on all sides so make sure that the correct side engages in the groove of the return bolt. Don't forget to secure the 4 screws.
We now come to the assembly of the shift rods. First, we insert the shift fork for 1st and 2nd gear and push the shift rod through. We press the locking ball down with a new tool when inserting it. Before hammering the switch rod into the housing, make sure that the slot in the rod is absolutely horizontal. The upper shift rings must not be forgotten either. Always check whether the gears can be shifted properly. You can make an auxiliary tool for this purpose, which we will also describe in more detail in the next issue of the DKW Praxis.
The shift fork and shift rod are used for reverse gear in the same way. Now we put on the 3rd gear, the drive sleeve and the circlip. Make sure that the 3rd gear wheel still has an axial play of at least 0.1 mm on the shaft. The same applies to the 2nd gear wheel. Now the sliding sleeve is inserted together with the shift fork and the shift rod. Make sure that the ring groove in the sliding sleeve still points towards the third gear rod. Now we can insert the locking plate for the shift rods. File it before inserting and make sure it goes in easily, otherwise a second dismantling may not be possible. When all the shift rods have been installed, the shift forks must be precisely positioned in the grooves for the shift lever. At the same time, make sure that the shift forks have a little bit of air against each other.
Now we insert the oiled needle bearing into the 4th gear, clean the butt areas of the two housing halves and beat them together. For this purpose, we insert the main shaft into the needle bearing, ensure that the teeth mesh correctly and are able to overcome resistance when the shift rod moves for 3rd and 4th gear. To do this, hit the screw of the retaining washer for the ball bearing and the return beam, which is near the shift rod for 3rd and 4th gear, with a hammer.
When screwing the housing together, note the following: In addition to the through-bolts on the differential, there is one screw 50 mm long, 2 screws 45 mm long and 2 screws 40 mm long. The order for reassembly is as follows (viewed from above) - The 50 mm long screw goes into the hole closest to the switch tower, then the two 45 mm long and at the bottom the two 40 mm long screws. It is essential to follow the sequence, otherwise there is a risk that you will burst the housing with a screw that is too long. When tightening the screws, start from the middle, i.e. first the two screws in the differential that are closest to the gearbox and then tighten the remaining screws. Now the bearing for the countershaft 00625-031-40 is hooked up to the rear stop and the circlip is put on. Now we switch on two gears and put the washer, the helical gear for the speedometer drive, lock washer and nut on the fourth gear. Now we can take out the 2 gears again and put the speedometer housing on.
On the right half of the housing (on the left in the direction of travel), before screwing on the differential flange with the inscription "left", a 1 mm thick shim is placed on the ball bearing. Then we press the ball bearing into the left half of the housing (on the right in the direction of travel). The bearing is pressed in so far that it rests against the differential housing. The required shims are placed on the bearing, and then the differential flange labelled "right" can be screwed on. Now the universal joints are put back on. Take the temporarily attached outer driver again (now again pay attention to the needles in the bearing blocks) and pull the inner driver onto the polygon profile. We will also develop a mounting sleeve for this. Make sure that the driver is hit up to the rear. Then the castle nut is screwed on and splinted. Now the outer drivers can be put back on. After loosely reinserting the screws between the outer driver and the associated bearing blocks, we clamp the bearing blocks together with a screw clamp so that they fit into the guide of the driver. Pay special attention to this. If a hammer is used here, damage to the bearing nodules in the lugs can easily occur. In the case of cars that have been running for a long time, we recommend checking that the play in the bearing blocks is within the normal range before assembling, leaving out the cork blocks. If this is the case, the cork plates are put back on and the joints are assembled as described above. If the play is too great, the braid cross must be replaced.
Now, if clutch has been completely dismantled, the ball bearing, the Seeger ring and the Simmerring (with the lip facing the gearbox) are reinserted into the clutch housing. Make sure that the chain is placed together with the coupling sprocket. Now push the coupling sprocket with the chain on the spline, put on the locking plate and screw it with the nut. The spacers, which regulate the chain alignment, are placed and the clutch bell is pressed into the bearing as far as it will go. The drive sprocket on the crankshaft is also inserted into the chain and the coupling housing prepared in this way is plugged onto the screwed-in stud bolts of the gearbox and motor housing and screwed. In order not to damage the lip of the Simmerring in the clutch housing, a protective sleeve (which is also being developed) must be used. Next the drive sprocket is screwed onto the crankshaft. The drive plate is put on and then the pressure plate, which must be tightened evenly. The clutch bell and the drive plate must be free of grease and oil. Once this is done, the clutch cover, equipped with the clutch control and the graphite ring, can be put back on. The compression springs in the clutch cover must be checked for perfect condition.
As you can see, the chain track is locked once and for all. Of course, the spacers must not be forgotten. With regard to the adjustment of the chain alignment and the test of the sag, we will work out control information and will come back to this in the next issue.
Finally, we provide a little more technical information about the gearbox:
The differential ratio is 3.4; the small drive pinion has 17 teeth and the large differential gear has 58 teeth. The drive wheel on the crankshaft has 25 teeth, the large rod on the clutch shaft has 46 teeth.
The ratio between the crankshaft and the drive of the front wheels is calculated from this as 6.27. The transmission ratio in 4th gear is 6.27 compared to 7.0 in the three-gear transmission.
The overall transmission ratios in the individual gears are now: reverse gear 1/40.02; 1st gear 1/31.12, 2nd gear 1/18.38, 3rd gear 1/10.16, 4th gear 1/6.27.
The gear ratios in the transmission are calculated directly: reverse gear 1/6.38, 1st gear 1/4.96, 2nd gear 1/2.93, 3rd gear 1/1.62, 4th gear 1/1.
1952 DKW Praxis Volume 6 - new tools for the DKW F700cc engine and gearbox
In issue 5 of the DKW Praxis, we gave you instructions on how to dismantle and reassemble the 700 cc engine with four-speed gearbox. Today, as promised, we want to introduce you to the special tools you need and give you instructions on how to use them. As you have already known, the engine with four-speed gearbox has a new single-disc dry clutch F and S K l 0. The construction of this clutch should not cause you any difficulties as the normal tool with 3 clamps for the clutch pressure plots under the 3 spring clamps will work, as the illustration shows.
If you neglect to unclamp these clamps, the release mechanism with the graphite ring will still be pressed outwards by the tension springs and you will have difficulties closing. The length of the 6 screws around the clutch pressure plot is not sufficient to be able to thread them into the thread holes.
If you want to remove the intermediate housing in which the triplex chain runs and the sprockets are located, you must first loosen the nut for the small sprocket from the crankshaft. For this work we developed a counter holder, no. 0100362-0, which, as the illustration shows, is simply put on the stud bolts of the housing and with its 3 pins pushes into 3 tooth gaps of the small chain rod and holds it in place.
You can then loosen the nut on the crankshaft with a normal socket wrench. To pull off the sprocket on the crankshaft, we use our well-known puller no. 0968, which will be lengthened a little in the future so that it can be held more easily. You can also use the pullers that are now in your warehouse and then only have to fetch the maul key to hold the puller at a slight angle. (Don't forget to push the thrust piece no.01000160 onto the crankshaft end beforehand.)
As we have already mentioned, the rubber joint can be dismantled without difficulty. If the inner driver cannot be easily removed from the polygon profile, you only need to use 2 screw bolts - No. 01008 and you can easily loosen it by tightening the pressure nuts.
To unscrew the castle nut of the inner driver, we tightened it with the counter-holder No. 0990, which you already know. As soon as the final dimensions for the reinforced rubber joint are known, we will check whether this counter-holder needs to be changed. We will then give you a separate message about this.
If we want to loosen the castle nut in front of the inner driver on the metal joint, we use the new counter-holder no. 0100363-0, the application of which you can see from the picture on page 4. It is simply pushed over the tabs of the inner driver and now allows the driver to be easily held. If the inner driver is stuck on the polygon profile, you can easily use it with a commercially available two-block puller. Such a two-jaw puller is assumed to already be in your workshop; if not, you can get it at any decent tool store. You will need it in a few other places with the four-speed gearbox but it will also serve you well in many other jobs. We do not intend to carry this puller as a special tool for the time being.
In our work instructions in the last booklet, we already pointed out that you have to have pliers for inner and outer circlets available and in good condition. From the sectional diagrams on page 17 of the last issue, you have surely seen that we removed a number of Seeger rings and put them back on when reassembling. You can never do this job properly without good circlips.
Now we come to the separation of the two housings half. We have already written that two extractors are being prepared with which this work can be carried out. You can see from the picture how these two pullers have to be applied. One puller, no. 0100366-0, is placed on the differential, the other, no. 0100367-0, with one pressure piece on the main shaft and with the other. The tool can of course still be used for the old engines despite the new bevel. Only use the tool on the side of the locking plate on which the gear housing is mounted. If you put it on the other side, you could damage the case.
Since the shift forks of the shift rods for the 3rd and 4th gear and for the reverse gear are removed when the rods are knocked out, the locking ball and the locking spring fall out and you have to press them back in when reassembling the gearbox. For this work we had previously developed the pin for locking ball No. 0100224. You can continue to use this mandrel, only you now need to have a flattened end. Flatten the side a little so that you can really push the ball in so that the shift fork can be pushed open. We have now lifted this tool slightly modified and at the same time provided a button at the rear end so that the pressure on the palm is not so great. If you already have the mandrel 0100224 in your possession, you can cut a piece of thread yourself at the back and press a small button, such as the one used for. B. occurs in our freewheel actuation, unscrew. You can also relax with us with the new pin for locking ball, No. 0100224-7. The button is already on this tool and the bevel is correct, so that no rework is necessary. Bear in mind that with the four-speed gearbox the locking balls fall out each time it is dismantled, so this tool is used much more often than it was necessary with the three-speed gearbox. Therefore, it should definitely be recommended to purchase the new tool or to rework the one you already have in the suggested sense.
Flatten the side a little further so that you can really push the ball in so far that the shift fork can be pushed open. We have now lifted this tool slightly modified and at the same time provided a button at the rear end so that the pressure on the palm is not so great. If you already have the mandrel 0100224 in your possession, you can cut a piece of thread yourself at the back and press a small button, such as the one used for. B. occurs in our freewheel actuation, unscrew. You can also relax with us with the new pin for locking ball, No. 0100224-7. The button is already on this tool and the bevel is correct, so that no rework is necessary. Bear in mind that with the four-speed gearbox the locking balls fall out each time it is dismantled, so this tool is used much more often than it was necessary with the three-speed gearbox. Therefore, it should definitely be recommended to purchase the new tool or to rework the one you already have in the suggested sense.
We wrote to you in the previous article that you should always check the shifter rod window to see whether the gears can be shifted properly. We suggested that you make an auxiliary tool with which you can easily carry out this control. You can see this auxiliary tool in the illustration.
It is nothing more than a small plot of the kind we have always used to cover the hole in the gearbox after the switch tower has been removed. However, this plate is only half the size, so it leaves the grooves in the goblets that the gear lever engages free. A lever with an elongated hole is attached to this plot. At the front of the lever there is a bolt that engages in the groove of the shift fork. It is useful if the foot end of an old gear lever is used here.
When the inner driver hits the polygon profile, you need the drive-in sleeve no. 0100365-0, which we show you in the picture.
Its application is completely clear, but make sure that the inner driver is pushed back to its rear seat. If this is the case, the front edge of the inner driver should protrude a little beyond the polygonal profile so that the castle nut absolutely clamps the driver firmly.
To look out and inspect the ball bearings, we recommend, as we already wrote in the work instructions, to warm the housing around the seat to approx. 600 in every case. If you knock out or knock in ball bearings when they are cold, the seat in the housing must be loosened. It can even happen that the camp is so far in its seat loosens it so that it rotates in this seat instead of in the rollers.
We developed a drive sleeve for the ball bearing in the differenti
Now we come to the insertion sleeve for the oil seal in the clutch housing. This Simmerring must be used with the lip facing the gear. If you do not use the insertion sleeve No. 010027 4-1 for this work, there is always the risk that you will damage the lip of the oil seal. For this reason, you should always place the insertion sleeve on the spline of the main shaft before putting on the oil seal. It is removed again by sliding on the Simmerring.
In our article in issue 5 of the DKW practice, we informed you that we would give you more information about checking the chain through and the chain alignment.
If you unscrewed the clutch cover, you can see the small chain wheel and a small piece of chain through the hole in the intermediate housing. With the three-speed gearbox unscrewing the clutch cover, we lifted the entire chain freely in front of us, so we can precisely determine the slack there by pressing the free chain ends between the two wheels. Unfortunately, this is not possible with the four-speed transmission. So all we have to do is lift the chain with our index finger to check whether it is too loose or not. An exact measurement is not possible. If the chain is too loose, it can be spun just like with the three-speed gearbox by inserting paper seals between the crankcase and the gearbox. However, we can only insert up to 1 mm in between with this engine, whereas we could insert up to 1.8 mm with the three-speed transmission.
The two chain wheels, namely the drive chain wheel on the crankshaft and the large chain wheel that sits behind the clutch, have to be aligned with one another in an engine with a four-speed gearbox. However, a tolerance of max. 0.2 mm permitted. Most of the time the drive sprocket will be too far forward on the crankshaft. You can correct this difference within small limits by tightening the fastening nut for the drive chain rod. However, if the difference in alignment is too great, you will have to put shims behind the coupling chain rod.
For measuring the chain track, we have developed a new gauge, No. 0100368-0, which can be used for both the four-speed and the three-speed transmission.
If you want to measure the chain track, take the clutch cover above, place the gauge on 2 of the studs at the inspection hole and push the sensor, turned to the left, against the ring gear of the clutch sprocket. Now push the knurled ring forward as far as it will go and secure it with the fashion screw. Then pull the ring with the sensor towards you a little, turn the sensor to the right and now press it onto the ring gear of the drive sprocket. When both gears are aligned, the knurled ring must rest against the stop. If the drive chain rod protrudes a little, you can measure the amount by which the chain alignment is incorrect directly on the knurled ring. You can even set the required shims by sliding them between the knurled ring and the stop, so that you know in advance how many shims you have to put behind the coupling sprocket.
On page 22 of the last booklet, bottom left, we talked about assembling the coupling. In addition to these explanations, it is important and essential to note that the semicircular millings must be placed in the hub of the coupling sprocket in such a way that they meet the two small holes in the spline. If you fail to do this, the bearing in the clutch housing will not receive any lubricating oil. So be sure to pay attention to this important point.
So, now we have discussed all of the special tools that are absolutely necessary and you clearly liked their use. As you can see, there are not many of them and they will certainly not be difficult to acquire. We expressly draw your attention to the fact that every DKW weighing workshop must have these special tools, otherwise work on the four-speed gearbox cannot be carried out. We would like to repeat them again with their order numbers so that no incorrect deliveries occur:
0100224-l Pin for locking ball
0100274-7 Guide sleeve for ring seal
0100362-0 counter holder for chain wheel
0100363-0 Counterholder for universal joint
0100364-0 Impact sleeve for ball bearings
0100365-0Impact sleeve for inner driver
0100366-0 Extractor for differential
0100367-0 Extractor for main and countershaft
0100368-0 gauge for measuring the chain track
Please submit your orders immediately. The special tools are expected to be delivered in 3-4 weeks. We hope that with these remarks we have told you everything you need to consider when dismantling and reassembling the four-speed transmission.
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