Clutch Master/Slave intermittently soft

[davidrn]

I washed my car last week, replaced the battery and then went for a short drive. After about 10 minutes I took it out on the highway, and the clutch dropped to the floor. I coasted to the next exit, and checked, the drive rod and spring were in place. Just no pressure left, and a full master reservoir. Limped home in second.
Today after a week of rainy weather, took the covers off, and was going to get it jacked up high enough to replace the slave. However, it is fine again, hence my intermittent subject line.
I don't see any prior mentions on the forum, anyone have an explanation?
I think regardless of any other new problems or suggestions of what could be wrong, I will replace the hose and fluid.

[69silver2k]

I am thinking that your seals in the master or the slave are bad... the pressure was fine for a bit, then the seal got twisted or bypassed somehow, sitting must have resealed the rubber. I think you need to do a little more investigation, I don't think the hose is the issue. good luck!

[bikermike]

Hmmmm

One thought is that it may be heat and fluid related. How old is the brake fluid in your clutch system and what color is it?

If it is old and black it has absorbed a lot of moisture. Upon getting hot, the brake fluid / water mixture in the slave is compressing causing the pedal to drop to the floor.

Yes, start with the hose and fluid. It can't hurt. Check past posts for advice on bleeding.
If it is moisture in your fluid, I'd suspect that a replacement or rebuild of your slave and master are in your future.

Good luck.

[mraitch]

I'd start by rebuilding the slave, then bleeding. The hoses mostly are quite reliable.
I think you can run something like acetone through the system to remove a lot of the gunk - then bleed vigourously.

[jrusso07]

Good advice from the list, one other thing to check is the slave hose. I had one that would balloon up under pedal pressure when hot. New hose made it well again.

[dbrick]

Good advise above, but, IMHO, if you plan to keep the car, just replace all 3 pieces ...It's can be as little as $100.00 to replace or rebuild it all it all, you make one mess and then it's done for the next ten years.

[bikermike]

I agree w/ Dave. Do it all.

If you want to diagnose, it would be interesting to test Joe's theory. Place a video cam under the car when warmed up and running and see if the hose balloons.

Some links:
Master: http://311s.org/phpBB3/viewtopic.php?f= ... lit=clutch
Slave: http://311s.org/phpBB3/viewtopic.php?f= ... =slave+kit

Note that there are 2 versions of the slave:
2" spacing of mounting holes
2 3/8" spacing of mounting holes

Check yours before you order one. The 2" one is harder to find and will be expensive.
I'd start w/ a rebuild kit: Beck/Arnley p/n 071-2414. It is common for both versions of the slave as the bore diameter is the same

[jrusso07]

I agree with Dave & Mike, do it all.

[JMartin]

I'd start w/ a rebuild kit: Beck/Arnley p/n 071-2414. It is common for both versions of the slave as the bore diameter is the same

Can this number be put in the tech WIKI, this could come in real handy in the future

[notoptoy]

I'd start w/ a rebuild kit: Beck/Arnley p/n 071-2414. It is common for both versions of the slave as the bore diameter is the same

Can this number be put in the tech WIKI, this could come in real handy in the future

Is this for the slave or the master?

[bikermike]

here are several p/n's in both of these threads:

Master: http://311s.org/phpBB3/viewtopic.php?f= ... lit=clutch" onclick="window.open(this.href);return false;
Slave: http://311s.org/phpBB3/viewtopic.php?f= ... =slave+kit" onclick="window.open(this.href);return false;

Beck/Arnley p/n 071-2414 is the rebuild slave kit - piston, seal and rubber boot.

[davidrn]

Thanks to all for the suggestions, by coincidence, I believe the only NOS part I got when I bought my car a few years ago was a clutch slave. My reason for the question was because their was no clutch one day, and back after sitting, that confused me. I will change the slave, hose, and the fluid (which I bet is old). Then we'll go from there.
Unfortunately the car has to wait, my grass is getting high and I have to repair the mule gear on my tractor, know thats going to take the rest of the weekend.

[dbrick]

My guess is it got full of air, which made it's way to the top and out to the reservoir as the car sat. where the air got in, now thats a mystery