Hey fellas,

A few months ago my clutch master cylinder was leaking so I replaced it. Clutch operated very normally till two weeks ago when the clutch started slipping on the highway. For example, I would be going 60mph at 2600 rpm or something, push down on the gas to get over a hill, and suddenly the rpms would jump up to 3500 and speed would not change.

The engine and clutch only have about 6000 miles on them and it was assembled properly, so I figured the slave cylinder might be having trouble. I bled it, and the clutch operation went back to normal. Sounds like it just got a little air in it, right?

Well a week later the same thing occurred, again corrected by bleeding the clutch. Does this sound like the slave cylinder needs to be replaced? Anyone had this trouble before?

 

don't forget i am the Y/T idiot when i answer this. have you had somebody pump the pedal to make sure the release cylinder is releasing all the way? generally, when the rpm's climb like you describe, the clutch is slipping. do you have a remain seal leaking, maybe? i know you said it is only 6000 mile since rebuild. that is my .01 worth.

 

I'd check that stuff out and if you know that the rear main seal is good, then I would also wonder about the front seal on the tranny. That seal went bad on mine and caused slipping. It's really easy to change...except for the whole removing tranny/trans thing!!!

 

A leaking seal would cause oil to get on the clutch and then it would slip all the time. That wouldn't explain why bleeding the clutch alleviates the symptoms.

And no, the rear main seal wouldn't leak after 6000 miles.

I'll change the slave cylinder and give you an update.

 

you are right.

maybe, depends on how it was installed.

sounds like a good place to start.

 

Did changing the slave cylinder fix the problem?

 

May be your slave , if your having to bleed it repeatedly then air is getting in the system somewhere and unless you see a visible line leak then that would be the place to go , after all its only a few things envolved with the air in the system problem unless you have trapped air in hydraulic clutch system and it is migrating .
Oil leaks at Trans or Main Seal would have to be very substanstail generally to cause slippage and the slippage is generally pronounced across the operating range so I don't think that is your problem.
Check for leaks closely and bleed the system well , if slave is bad enough to cause that it generally is leaking also but can have a problem with the cylinder sticking from wear or varnish without leaking as well , hate to see you replace and then that not solve your problem but if the clutch installation is good then that would be the way to go since you have already replaced your MC taking for granted there are no leaks where system could suck air as well , when you have to bleed again is the fluid level lower at that point ?

 

Well, I changed the slave cylinder, and it was doing fine for a while, then started having the same slippage problems.

I drove it around and then cracked open the slave cylinder bleeder - there was pressure! So that means the system was not de-pressurizing. I checked the FSM and it said to adjust the pedal to have 5 to 15mm of play. The pedal had NO play at all. I adjusted it and it seemed to fix the problem! I'll update after I drive it some more...

 

Cool , let me know what happens , maybe replacing old MC changed that , good to know that kind of stuff .

 

Here's the update guys, the truck behaved itself for a while but now it acts up intermittently. Seems like if I pump the clutch a few times it will begin to grab better...

Also, the clutch does not start to grab at all until the clutch pedal is about 1/2 way up, and even when it was working it was still soft...

Any more ideas guys?

 

If you pump the clutch a few times and it grabs better, then it sounds like you've got air in your system. Check out the rubber hose near the slave cylinder for leaks.

Also, it's possible that either your MC or SC, or both, are not doing their job. If you have air in the system, it doesn't take long before the aforementioned break down due to poor lubrication. Did you bench bleed the MC?

One more thing is to look at your clutch pedal bracket to make sure there aren't any cracks which may limit the travel of the push rod in the MC.

 

I would say carefully and thoroughly bleed that booger .

 

Here's a new element guys - I just called a mechanic and told him my woes, and he said that my problem is probably that I replaced the MC with an Advance part... In his experience items like that from Advance or Autozone do not hold up. This would explain why I got a good 6 months out of it but that was it. Looser tolerances, cheaper materials, etc.

I will be replacing it sometime soon (and probably the slave cylinder too), getting my money back from Advance, and I will update.

 

i agree with the above a friend of mine had the same issue with MC from Autozone. let us know how it works for ya.

 

Maybe but I would still bleed that booger real good , hate to see you buy both and only really need one .

 

get real toyota parts when it comes to hydraulics. apparently the cheapo rebuilts don't last at all. i used cheap rebuilts when i did my clutch and it's already giving me notchy shifting after only a few thousand km.

 

OEM Baby !!!!!!!!!

 

i agree with the above worth it toyota makes ome amazing parts.

 

Just a quick question - if my MC was leaking internally, would it not just cause the clutch to be hesitant to disengage, not hesitant to engage?

 

Make sure you check that piece of flex hose on the passenger side of the fire wall. It's a common point of leaks.