MR2 SpyderChat banner
1 - 20 of 33 Posts

·
Registered
Joined
·
7 Posts
Discussion Starter · #1 · (Edited)
SMT GSA Oil Leak

The SMT GSA started to leak at the clutch actuator. Because of the cost, I decided to take it a part and try to replace the seals.


A bit of German engineering, but no too hard to work on.
It Has now worked for a week. Also use DOT with 10% castor oil as hydraulic fluid.
 

·
Registered
Joined
·
7 Posts
Discussion Starter · #2 · (Edited)
Update 2/23/13

It has now been working flawlessly for about half a year.

If you replace a seal in the system, make sure it is of EPDM. The only rubber compatible with brake fluid. Standard Buna-N will swell and start to leak.

If anyone needs the seals to fix a leaking clutch actuator, send me a message. Have a few extra.
 

·
Registered
Joined
·
7 Posts
Discussion Starter · #4 ·
Couldn't find the seals from any regular manufacturer. Had seal-direct.com to make them for me. They have a setup charge, so I had them to make me a few extra. If you need a set I will let you have it at cost.
 

·
Registered
Joined
·
1,814 Posts
Gosh, I wish I knew you had a set for sale Cyclehead. I had asked Stefan months ago if he had any left. My daughter's car is leaking fluid. I was curious what it would cost to have the seals made.
 

·
Registered
Joined
·
8 Posts
do you still have a seal?

Update 2/23/13

It has now been working flawlessly for about half a year.

If you replace a seal in the system, make sure it is of EPDM. The only rubber compatible with brake fluid. Standard Buna-N will swell and start to leak.

If anyone needs the seals to fix a leaking clutch actuator, send me a message. Have a few extra.
Do you still have a seal?
 

·
Registered
Joined
·
5,005 Posts
I got the clutch actuator end-plug out. I grabbed the swaged cable end with vice grips, then stood on the GSA and yanked. Hard.

I disassembled all three actuators to scope out seals for them also.
I'm trying to understand the dual seal arrangement in the two gearshifter actuators.
There is an inner o-ring, and a stiff outer seal. The outer seal has a rectangular cross section, and feels stiff like teflon.

The shifter actuators appear to get dual-side pressure (?), where both sides of the piston have a fluid port. I'm thinking that leakage past the outer (teflon?) stiff seal doesn't matter, since both sides of the piston see fluid, and the computer monitors piston position constantly. A little leakage would just prompt the computer to port a little more pressure to one side or the other.

The clutch actuator though is different. It only has one pressure port. If fluid leaks past the piston seal, I think the leaked fluid will piss outside the GSA. Maybe that would be why more folks are reporting the clutch actuator leaking recently.

The top two are the gearshift pistons. The bottom one is the clutch actuator piston.


Here's the dual-seal on the two gearshift pistons. Outer seal is hard plastic, inner is a normal o-ring.




View looking into the clutch actuator bore. Only one fluid port.


View looking into one of the gearshifter actuator bores. One port in the bottom and another at the top of the bore.
 

·
Registered
Joined
·
1,814 Posts
The square seal might be Teflon, the same as the hydraulic cylinders I've rebuilt on my skid-steer. Do you remember whether Stefans was Teflon or EPDM? I would think Teflon. The "o"-rings are surely EPDM. Wood
 

·
Registered
Joined
·
5,005 Posts
The square seal might be Teflon, the same as the hydraulic cylinders I've rebuilt on my skid-steer. Do you remember whether Stefans was Teflon or EPDM? I would think Teflon. The "o"-rings are surely EPDM.
As you say - I found a generic schematic showing the "PTFE Piston Ring" style. That's what LUK did on the two shifter actuators, but not on the clutch actuator.

Stefan got seals made only for the clutch actuator, which does not have the teflon ring. So his seals were EPDM material only. They look more like the "unloaded U-cup style".

 
1 - 20 of 33 Posts
This is an older thread, you may not receive a response, and could be reviving an old thread. Please consider creating a new thread.
Top