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StevenHansen
Samba Member
Joined: January 26, 2019
Posts: 33
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 Posted: Tue Nov 26, 2024 10:20 pm Post subject: 1969 VW 411 clutch cylinder leaking |
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Hi
I have bought a 1969 VW 411 that has been in a museum here in Denmark, Europe for 32 years.
It had no clutch as the fluid was very low. After I put fluid in the reservoir, there is now clutch, but the cylinder under the dash is leaking down the clutch pedal. Not much, but it is leaking.
Does anyone know where I can get a new cylinder or a rebuild kit for those? Or can I use something from another model?
Is this a one year only? I was told the slave cylinder on top of the transmission is different than on the other years, don't know if it's correct.
Thanks in advance.
Regards Steven. |
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raygreenwood
Samba Member
Joined: November 24, 2008
Posts: 23002
Location: Oklahoma City
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| Posted: Wed Nov 27, 2024 8:53 am Post subject: Re: 1969 VW 411 clutch cylinder leaking |
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| StevenHansen wrote: |
Hi
I have bought a 1969 VW 411 that has been in a museum here in Denmark, Europe for 32 years.
It had no clutch as the fluid was very low. After I put fluid in the reservoir, there is now clutch, but the cylinder under the dash is leaking down the clutch pedal. Not much, but it is leaking.
Does anyone know where I can get a new cylinder or a rebuild kit for those? Or can I use something from another model?
Is this a one year only? I was told the slave cylinder on top of the transmission is different than on the other years, don't know if it's correct.
Thanks in advance.
Regards Steven. |
 .....you people drive me crazy!
It seems like every time I am just about 3/4 finished with a major pictorial "How to repair this part"...post....you ask about it before I am ready to post it! 
OK.....the early 411's until probably right at the 1970 to 1971 changeover (which means that very few ever made it to the US).....use the same master cylinder as all 411/412 manual transmission cars but they use a slave cylinder that is half the diameter of the late model, with a longer stroke and therefore a different pivot point to make the clutch bearing throw the same across all years.
The early 411's used a 22.25mm slave cylinder bore. The later models mostly export 411 and all 412's used a 44.5mm slave cylinder.
For decades I have been working to get parts for these clutch master and slaves. I have finally solved the internal sealing issue. I am now working on the bore issue and the outer boot issue, mainly for the more common 44.5mm cylinder.
Very luckily....if you convert those two bore measurements to inches....you get 22.25mm = 7/8" and 44.5mm = 1.75". These are two very common SAE seal sizes.
Recently I have been able to find a very good seal and o-ring company here in the US that has a U-cup seal that can be backed by an o-ring that is the exact size ID and OD for the 44.5mm seal....and most importantly it is the correct material....EPDM and is very high quality and are in stock and cheap.
They have seals in 7/8" OD that will fit the earlier 411 cylinders...but I have no idea what size the ID is or the seal groove wdith on those early master cylinders.
So........
There are three items that I can guarantee are totally broken in your clutch system and MUST be replaced:
1. The master cylinder internal U-cup. This one is the easiest to work with. The type 4 master cylinder is a 19.05mm bore just like some type 1 and all type 3 and 4 brake master cylinder.
You can take the outer bore seal and the outer piston inner seal right next to the spring and put them on your clutch master cylinder pistons....and use your original piston and spring and you are done.
Also, the Vanagon clutch master cylinder is the same diameter and stroke. So you can get a Vanagon clutch master cylnder rebuild kit and take all of the parts except the piston and put them into your master cylinder and you re done.
In a pinch, I can show you how to take a piece of steel angle iron and fashio na bracket to allow using the complete Vanagon clutch master cylinder in your car. You cna make it bot right up.
The vanagon clutch master cylinders are readily available and fairly inexpensive. Buy an FAG or ATE brand. Once you get one you can decide if its easier to swap the parts from it into your original or simply build a bracket to bolt the Vanagon cylinder into your car.
https://www.fcpeuro.com/products/vw-clutch-master-...guEALw_wcB
So, the problems you MAY find with your origina master cylinder are rust in the bore and corrosion on the piston. Remove it, disassemble it and clean the piston with steel wool and post pictures of what you find. Measure the piston head with a caliper/micrometer in cylinder spots. It the piston head flanges next to each seal are still round...your piston is fine to use again. If you notice that its not round and you see what looks like scuffing (which is actually corrosion)...you need a new piston.
Wrap some 600 grit wet/dry sand paper around a rod and spin it in the bore to LAP the bore clean. Check for any deep rust pits. Use nothing more rough than 600 grit. If you have no deep rust grooves or pits ....your cylinder is fine to rebuild and reuse.
2. There is a 30" long rubber hose that starts at the tail of the transmission where the steel line attaches and goes all the way to the slave cylinder. Nearly 100% of the time this will be rotted. Its a bad design. There is no reason for a flexible hose right here.
You can do two things.
A. bring this to a hose shop and have a duplicate made. Keep in mind that you will be replacing it again in 10 years.
B. This is a better method. Go down to an industrial tubing shop and buy a length of steel tubing the right diameter. Then buy a STEEL high pressure union (not a brass one like you use for water).
Get a short length of the same tubing at an automotive house that has the proper male 12mm fitting to fit the slave cylinder. Get a short piece with the male fitting for the other end. Join them to the long piece of tube with the high pressure fittings (which are typically good to about 3000 psi).
Then buy a stock Vanagon clutch slave cylinder connector hose. I will post the part number later.
What this will give you is a short 12" long flexible joint line right at the tail of the transmission that bolts right into the original bracket on the transmission and uses the stock factory spring clip. It looks just like factory. From there you have a solid steel line that goes stright to thesave cylinder. When you buy the right parts this wil be about $30 and about 1 hour of time ....far cheaper and more reliable than trying to have the factory rubber hose re-made.
3. You needto pul teh slave cylinder and dissasemble it just like the master cylinder. Clean and lap it just like the master cylinder. Carfully store the outer boot. It may not be easy to source.
Carfully cut off the old seal inside. Measure it and post a picture. I can fnd you the seal.
Its also quite possible....and I would bet money on it....That it is the same dimension seal as the Vanagon slave cylinder....and if so, you can use a Vanagon slave cylinder rebuild kit for its seals......NO...wait...sorry. The Vanagon uses a 25mm seal. Sorry.
I can find 7/8" seals for you.
Start with this and show us what you have when you get it out of the car.
EDIT:....be careful....for the 1970 model year there were (so the book says) about 6000 cars made with a 17.46mm diameter master cylinder. I have never seen one. This does not mean you might not have one.
Ray |
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StevenHansen
Samba Member
Joined: January 26, 2019
Posts: 33
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| Posted: Wed Nov 27, 2024 11:42 am Post subject: Re: 1969 VW 411 clutch cylinder leaking |
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Thank you very much for the great description.
I will try to look into it and I hope my skills are enough.
Do you have a picture of the bracket that would be needed to convert it to a Vanagon T3 master cylinder?
Also do you have a picture of how that industrial hose and connection should look like for the clutch slave cylinder and the part number for the Vanagon T3 one?
Also, how do I get the two cylinders off the car the easiest and best way?
Regards Steven. |
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raygreenwood
Samba Member
Joined: November 24, 2008
Posts: 23002
Location: Oklahoma City
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| Posted: Thu Nov 28, 2024 8:10 am Post subject: Re: 1969 VW 411 clutch cylinder leaking |
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| StevenHansen wrote: |
Thank you very much for the great description.
I will try to look into it and I hope my skills are enough.
Do you have a picture of the bracket that would be needed to convert it to a Vanagon T3 master cylinder?
Also do you have a picture of how that industrial hose and connection should look like for the clutch slave cylinder and the part number for the Vanagon T3 one?
Also, how do I get the two cylinders off the car the easiest and best way?
Regards Steven. |
Getting the cylinders and parts out are fairly easy. Of course, there may be some visual differences in a 1968, but it should be close enough.
Sitting in the divers seat (assuming left hand drive) there should be a small triangular plastic shelf down by your knee and in front of the fuse panel. It should be held on by 4 or 5 sheet metal screws. Remove that shelf.
Next, there should be a fiber-board cover that covers up the underside of the steering column and the pedal assembly. It should have two screws with washers and maybe a 3rd small screw that holds the fuel pump relay to the pedal cluster assembly.
Carefully remove that cardbard cover. They are unavailable and rare. It is fragile.
Before you go any further , take a syringe or suction tube and draw down any remaining fluid in the clutch side and some from the brake side in the master cylinder reservoir.
Once that cover is off, look at the left hand side of the pedal support assembly. Lots of wires down here but follow the clutch pedal up and you will see the clutch master cylinder and its steel line.
First take two wrenches I think it requires a 15mm and 17mm. The larger wrench is to hold the gold colored residual pressure valve still while you loosen the flare fitting on the line.
Keep a towel/rag underneath to catch any leaking fluid.
There are two M10 bolts holding the master cylinder to the pedal assembly. They take either a 17mm or 19mm socket. Remove those and slide the master cylinder toward the drivers seat to remove it from the pushrod assembly. Now you only have to pull out the feed line from the reservoir. Again, make sure you have rags to catch leaking fluid. The Master cylinder is not removed.
The clutch slave on your early model car is a little less convenient to remove than the later models. I have never had to remove one while the transmission is in the car.
You should put the rear of the car up on stands with the tires just off the ground so you have room to work. Typically it really helps to remove the left hand wheel.
Your slave cylinder is held into the boss on the transmission with a snap ring and circlip. Here is the diagram and Haynes manual directions:
First remove the supply line. This is where you will see that rubber pressure hose I was speaking of.
There may be a rubber cover that is covering all of this. Remove that next.
Then you will see a spring hooked to the end of the clutch slave piston on the forward side of the clutch fork/lever. Remove that.
Then the snap ring, then the circlip and metal clip and slide the cylinder toward the rear of the car. Hopefully it will not hit the firewall and block you from taking it out.
In cars that have not had the cylinder removed for a long period, you may need to spray some penetrating oil around the cylinder to break it loose.
Ray |
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StevenHansen
Samba Member
Joined: January 26, 2019
Posts: 33
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| Posted: Thu Nov 28, 2024 8:45 am Post subject: Re: 1969 VW 411 clutch cylinder leaking |
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Thank you again for your help. I will let you know when I have removed it. I will start with the clutch master cylinder that is leaking.
Do you have a picture of the bracket that would be needed to convert it to a Vanagon T3 master cylinder?
Also do you have a picture of how that industrial hose and connection should look like for the clutch slave cylinder and the part number for the Vanagon T3 one? |
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raygreenwood
Samba Member
Joined: November 24, 2008
Posts: 23002
Location: Oklahoma City
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| Posted: Thu Nov 28, 2024 9:35 am Post subject: Re: 1969 VW 411 clutch cylinder leaking |
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| StevenHansen wrote: |
Thank you again for your help. I will let you know when I have removed it. I will start with the clutch master cylinder that is leaking.
Do you have a picture of the bracket that would be needed to convert it to a Vanagon T3 master cylinder?
Also do you have a picture of how that industrial hose and connection should look like for the clutch slave cylinder and the part number for the Vanagon T3 one? |
I will get some pictures of mine in the next day or so and will have the part number for the hose at the same time.
At one point in time when parts were just not available for the type 4 master cylinder, I actually had a Vanagon master installed. I no longer have it but I can sketch the bracket. Its very simple and if you held one of each cylinder in your hand next to each other it would be very self evident.
Ray |
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StevenHansen
Samba Member
Joined: January 26, 2019
Posts: 33
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| Posted: Thu Nov 28, 2024 9:37 am Post subject: Re: 1969 VW 411 clutch cylinder leaking |
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| Thank you. |
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