Clutch master fluid

[Storman Norman]

As I am a new owner of what once was my Uncle's car before he passed and am jumping into this Cobra screen. I am a Mechanic but that doesn't mean I know it all. After running this car a while the clutch began to drop off like the slave cylinder was leaking and the reservoir was empty. Looked in the reservoir and it had fluid. tried to bleed the slave but it would not bleed right so I removed the reservoir and dumped it out to find a bunch of crud like someone used the wrong fluid and caused one of the fluids to turn into lumps which is probably plugging the master cylinder. This brings me to my question. I have a Superformance MKIII and I am wondering what is the correct fluid for this master cylinder? Is this a Mineral oil or a Dot 4 system?

[twobjshelbys]

Mine behaved exactly like this with the dirty fluid and losing fluid. It was the master cylinder gaskets all caused by the fact that the master and, in my case, the hydraulic throw out bearing, were not properly aligned. You can replace the master but depending on which manufacturer it might have a rebuild kit. First I rebuilt the master cylinder, then I had to rebuild the HTOB, and after the second time the HTOB ate the gaskets I ditched the whole setup and went to a more traditional master/slave setup.

[cycleguy55]

Originally Posted by Storman Norman

As I am a new owner of what once was my Uncle's car before he passed and am jumping into this Cobra screen. I am a Mechanic but that doesn't mean I know it all. After running this car a while the clutch began to drop off like the slave cylinder was leaking and the reservoir was empty. Looked in the reservoir and it had fluid. tried to bleed the slave but it would not bleed right so I removed the reservoir and dumped it out to find a bunch of crud like someone used the wrong fluid and caused one of the fluids to turn into lumps which is probably plugging the master cylinder. This brings me to my question. I have a Superformance MKIII and I am wondering what is the correct fluid for this master cylinder? Is this a Mineral oil or a Dot 4 system?

The manual update I found at https://www.secondstrike.com/Technic...V37_Update.pdf says the following:
Any DOT 3 or DOT 4 or DOT 5.1 fluid can be used. DO NOT use DOT 5.

Also of note is the following:
The clutch slave cylinder seals have a tendency to fail after several years. Consider replacing the slave cylinder every five years as preventative maintenance. If the fluid is black when bled, change the slave cylinder now.

[Gaz64]

Originally Posted by Storman Norman

I am a Mechanic but that doesn't mean I know it all.

Glad to see another admits to that statement.

39 years for me, and I'm still learning something new everyday.

Some young guys think they know it all these days.

Gary

[pgermond]

I use DOT 3 or 4. My clutch m/c was dying so I decided to replace it. It was filled with sludge that I equate it to 13 years of driving and the hydraulic line being close to the header (lots of extreme heat). You can also use Wilwood hi-temp 570 racing brake fluid, but not necessary.

[Andrewyoung78]

my clutch slave dump all the fluid out and after replacement and bleed the slave, the clutch grab almost at the top and clutch slip under load in third gear. It doesn't appeal to have any more bubble in the system. What else I should look at. Thanks.

[Gaz64]

Originally Posted by Andrewyoung78

my clutch slave dump all the fluid out and after replacement and bleed the slave, the clutch grab almost at the top and clutch slip under load in third gear. It doesn't appeal to have any more bubble in the system. What else I should look at. Thanks.

Sounds more like worn out clutch plate or weak pressure plate.

Internal or external slave cylinder?

Gary

[Andrewyoung78]

external slave from Napa, matching the one superformance installed. The pressure plate and everything else were fine prior to the leak from the slave.

[Gaz64]

Andrew, you should start a new thread, rather than changing the subject and show respect to the original thread creator.
Gary

[hauss]

Look close at the master I have a backdraft but the operation is the same.I changed three slave cylinders before realising it was the master the whole time.