I'm new here and I'm currently trying to get a '74 412 back on the road. I'm in need of finding cups for my clutch master cylinder. I posted this question on the thesamba.com and was given a link to this forum. (great forum by the way!) I have read though most of the old posts on this topic.
Some posts say that the cups from a type 3 master cylinders fit the 412 clutch master. There are also references to the Rabbit clutch/brake master, or the Vanagon's. What should I be looking for?
Thanks in advance.
Dan
Clutch master cylinder
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raygreenwood
- Posts: 11912
- Joined: Wed Jan 22, 2003 12:01 am
The best exact fit in type 3 cups is to find a type cylinder of the same brand as teh type 4 cylinder you are rebuilding. There are very slight difference make to make.
i.e.: Its best to put seals from an FAG cylinder back in an FAG and a Teves back into a teves.
They will all work...but for best long term outer seal life and work...there were very slight difference in the shape vs the shape of the piston.
The brazilian made rabbit cylinders are kind of in the middle and work decently on both Teves and FAG.
Use the seals and the brass flap valves only. The springs are OK too...but swapping pistons is a no-no.
The vanagon seals work very well. In fact...by building a small "L" bracket you can plug the vanagon cylinder right in. You may need an adaptor for the residual pressure valve. Ray
i.e.: Its best to put seals from an FAG cylinder back in an FAG and a Teves back into a teves.
They will all work...but for best long term outer seal life and work...there were very slight difference in the shape vs the shape of the piston.
The brazilian made rabbit cylinders are kind of in the middle and work decently on both Teves and FAG.
Use the seals and the brass flap valves only. The springs are OK too...but swapping pistons is a no-no.
The vanagon seals work very well. In fact...by building a small "L" bracket you can plug the vanagon cylinder right in. You may need an adaptor for the residual pressure valve. Ray
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danomight
- Posts: 10
- Joined: Fri Jul 04, 2008 7:37 am
Thanks Ray,raygreenwood wrote:The best exact fit in type 3 cups is to find a type cylinder of the same brand as teh type 4 cylinder you are rebuilding. There are very slight difference make to make.
i.e.: Its best to put seals from an FAG cylinder back in an FAG and a Teves back into a teves.
They will all work...but for best long term outer seal life and work...there were very slight difference in the shape vs the shape of the piston.
The brazilian made rabbit cylinders are kind of in the middle and work decently on both Teves and FAG.
Use the seals and the brass flap valves only. The springs are OK too...but swapping pistons is a no-no.
The vanagon seals work very well. In fact...by building a small "L" bracket you can plug the vanagon cylinder right in. You may need an adaptor for the residual pressure valve. Ray
Just to clear things up. We are talking about a type 3 brake master, and the rabbit and vanagon clutch master? Is this correct?
On ebay there are some type 3 brake master rebuild kits. In the photos they show one cup (no hole) that goes over the end of the piston and one cup (with hole) that fits around the piston. On my clutch master both cups fit around the piston and appear to be identical to each other. Would I need two type 3 rebuild kits to get the two cups I need?
I might go with the vanagon clutch master if I can't find replacement cups. Making a mount is no problem. Would I need to modify the clevis to the clutch pedal? -Dan
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raygreenwood
- Posts: 11912
- Joined: Wed Jan 22, 2003 12:01 am
The type 3 brake master seals will work inboth a type 4 brake master and clutch master. Just be sure that if you are using a specific brand in the type 4...you get seals from the same brand of type 3.
And we are talking about brake master cylinder seals from a rabbit going into either brake or clutch master cylinders from a type 4.
Only the vanagon had a hydraulic clutch like the type 4. It had the identical bore and stroke. It seals are a direct crossover...but the pistons are not.
The type 3 cylinders had no cups with no holes. You may have been seeing the outer dust boot.
the outer seals on all master cylinders have a cup with an inner second seal lip. These are called a "shaft seal" type of seal. They are designed to keep fluid from seeping around the piston and leaking to the outside. Ray
And we are talking about brake master cylinder seals from a rabbit going into either brake or clutch master cylinders from a type 4.
Only the vanagon had a hydraulic clutch like the type 4. It had the identical bore and stroke. It seals are a direct crossover...but the pistons are not.
The type 3 cylinders had no cups with no holes. You may have been seeing the outer dust boot.
the outer seals on all master cylinders have a cup with an inner second seal lip. These are called a "shaft seal" type of seal. They are designed to keep fluid from seeping around the piston and leaking to the outside. Ray
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danomight
- Posts: 10
- Joined: Fri Jul 04, 2008 7:37 am
That clears it up for me. Thanks allot Ray.raygreenwood wrote:The type 3 brake master seals will work inboth a type 4 brake master and clutch master. Just be sure that if you are using a specific brand in the type 4...you get seals from the same brand of type 3.
And we are talking about brake master cylinder seals from a rabbit going into either brake or clutch master cylinders from a type 4.
Only the vanagon had a hydraulic clutch like the type 4. It had the identical bore and stroke. It seals are a direct crossover...but the pistons are not.
The type 3 cylinders had no cups with no holes. You may have been seeing the outer dust boot.
the outer seals on all master cylinders have a cup with an inner second seal lip. These are called a "shaft seal" type of seal. They are designed to keep fluid from seeping around the piston and leaking to the outside. Ray
I'm going to order a Vanagon rebuild kit for now. I think I will probably go with the Vanagon cylinder later when my rebuild starts to leak. Hopefully not too soon.
I'll keep you posted!