jhk94

I'm driving a 1986 2wd Pickup, 5 speed. Last winter, when it started to get really cold here in Iowa, my clutch started to slip really bad, especially once the engine was warm, and eventually wouldn't even go into gear. I bled the clutch and it was fine again.

Fast forward one year, it gets cold again, my clutch starts to slip again. I bled the clutch, and the fluid is filthy - black and opaque (though the fluid in the master cylinder reservoir still looked clean). I went through about 10 reservoir refills to flush it out, refilled, and the clutch is feeling good again, and works fine.

One week later, and now the clutch is slipping again! There aren't any leaks. Is it possible that water/dirt/etc is getting into my clutch system this quickly and gumming up operations? I could imaging dirt getting in through the seals on the slave cylinder, but is that likely? Would it leak water/dirt in, but not fluid out?

I had problems with this about 2 years ago, too, but in that case the slave was leaking like a sieve. Had the slave and master cylinders replaced and the system was flushed, though it was at pepboys and I don't know the quality of their parts (I was on the road at the time). Could the slave/master already be shot?

Thanks a lot! I feel bad making this my first post - in the past I have always had 100% success just searching and finding what I needed in old posts.

Stuwy123

iTrader: (1)

Maybe your clutch is toast.

jhk94

It's possible the clutch is bad, but why would bleeding the clutch fix the problem for a week? Also, I had the clutch inspected during some other work a little over a year ago, and it was in very good condition.

RustBucket

iTrader: (1)

Internal leaking in the clutch hydraulic system. Both slave and master cylinders are suspect. I've had this happen before.

Also are you losing fluid? Could be a slow leak, check the rubber hose to the slave.

jhk94

I haven't noticed any leaks or fluid loss, but it is possible (I will check again today).

RustBucket

iTrader: (1)

If the leak is internal you might not lose any fluid.

jhk94

Is there any way to really tell if its an internal leak? My first thought is just to replace the slave and master cylinders - would that take care of the leak?

RustBucket

iTrader: (1)

That's probably what I would do. Replace with high-quality Aisin units and not something from AutoZone.

jhk94

Great, hopefully that fixes it!

wyoming9

iTrader: (1)

you had the transmission out of the truck and did not put in a new clutch???

in Fact it was worse because the clutch would have had to be out to inspect it.

It might be possible your drawing in air and have a fluid leak so slight you really don`t notice.

Your fluid should not be getting contaminated it should stay nice and clean.

jhk94

Yeah... I was having trans work done, and the mechanic checked the clutch. I was going to have it replaced at the same time, but he talked me out of it because it looked pretty new. At the time I wasn't really flush with cash anyway, so I was mostly just happy to hear that.

Yeah, I was concerned at how dirty the clutch fluid had become after only about 10 months. I ordered a new aisin master and slave, so hopefully that will fix this up.

Marc

By slipping do you mean when you give it gas while driving the rev's go up?
I don't understand how it can both "slip" and you have trouble getting it into gear.

jhk94

Sorry, I misspoke there. I could move it into gear easily, but the clutch slipped so much that it wouldn't engage at all. Then I bled the clutch and it worked perfectly.

wallytoo

iTrader: (1)

that makes the issue less clear. if the slave wasn't fully extending, you'd grind gears when shifting. after bleeding, the slave would then fully extend, and the grinding would stop.

you are saying that just the opposite is happening, ie, that you could easily shift, but when releasing the pedal, the clutch wouldn't fully engage, and it would slip. bleeding shouldn't make that better.

the slave could be hanging in the extended position, not retracting once the pedal is released. that would allow easy shifts, and virtually no engagement once the pedal was released. perhaps the bore is corroded and catching the piston, preventing it from retracting. not sure why bleeding would remedy this, though.

Team420

Pressure plate is prolly toast.

jhk94

Now you that you say it, yeah, sometimes it was hard to get it into first (had to pump clutch or push really hard), but once I was moving it wasn't a problem. But it didn't happen all the time, and it wasn't always accompanied with slipping. We'll see if the new master and slave make a difference, and if not it might be time for a new clutch.

wyoming9

iTrader: (1)

I could see that if you had internal leaks bleeding the system would maybe get the fluid out from where it shouldn`t be.

As the fluid builds up restricting movement it starts to give you problems again.

I am thinking your new Master and Slave should cure your problem.

RustBucket

iTrader: (1)

I've had both situations occur due to clutch hydraulic issues. A Honda would slowly lose fluid and then you could no longer shift gears. My 4Runner one had a bad slave or master cylinder and it would cause the clutch to slip. I guess the pushrod wasnt allowed to retract fully.

jhk94

Well, I put in a new master and slave, and it looks like the probably is fixed. Shifts very easily, clutch is very easy to press, and no slipping at all after about 35 miles of driving. Let's hope it stays that way.

Before I changed it, the old fluid was clearly contaminated - particles and dirty looking after only 1 week of driving. The old master cylinder had some rust around the pushrod and seemed kind of corroded. The boot on the slave cylinder had a tear in it, too. So it could have been dirt/water coming in through the slave or problems with the master pushrod - hard to tell since I replaced both. Definitely better than a problem with the clutch itself!