clutch mastercylinder

[Kev-o]

Quick question, i am replacing my second clutch mastercylinder within a month, but this last time i went to start the truck and felt the clutch pedal a little heavy then bam, to the floor with brake fluid around the cylinder, i put a new one on and still got no pedal feel it was easy to bleed last time with the bleeder screw and i'm sure there was a little pedal feel right off the bat last time, could it be that the ball stud wore right through the pivot fork? and would it be correct that you can't bleed hydraulics if there is no resistance?

[Kev-o]

just got it bled false alarm guess it must be time to do the pivot fork and ball stud though.

[oilburnertoo]

Generally by the time you need a clutch/hydraulics the pivot ball and clutch fork are usually worn bad and need replacing also. There is a grease zerk on the bottom of the bellhousing [lubes the fork and pivot ball] that gets overlooked while doing routine maintaince. Just my experiance and 2 cents.

[Kev-o]

All right i have replaced three in under two months and i have a new spare in the truck till i have time to pull the tanny & T-case. but the last time i put the new one in i drove it about 15 miles then bled off the cylinder again, went to start the clutch and the pedal seemed to come back very slow, so i pumped it a few times and lost it all again. i looked in the cylinder and it white/milky/airbubbles. Any ideas? the previous owner was really good at maintenance and greased the zerk fitting when needed, new clutch 3500 style he has said and he also said they did not change the pivot fork/ball stud? PLEASE HELP ME WHAT NEXT?

[a5150nut]

The only times I have had trouble with Slave or Master cylinders has been related to moving the hard line between them arround too much. How are the motor mounts? And is the monting bracket being used on the line at the back of the bell housing? IIRC there was one there. It doesn't take very much movement or vibration in the metal line to stress the plastic housing at either end.

And on second thought, how much stress are you putting on the cylinder when R & R the roll pin that holds the line in? I usualy use a small nail cut off and a pair of channel locks. Take care not to twist or horse the plastic. Just slide the pin in or out.

[Kev-o]

Thanks i will check the line for brackets etc.., I had to replace the slave today as it too fractured? So now i am at 3 master cylinders and 1 slave cylinder, I do not understand why these are molded/cast from plastic, i think metal would hold up much better but i guess they work fine when the rest of the system is up to par? I have done a clutch job in my 6.2 blazer, is this r&r for tranny and t-case a fairly straight forward job to replace the pivot fork and ball stud ( the old owner said the clutch was replaced about 40,000 miles ago)?

[a5150nut]

post and stud arn't bad cept for the transfer case, transmision..........

Not any worse than doing the clutch. I just dont like working on my back that long. Someum to do with age I guess. Damn bi-focals, can't see at the right range, takem off, putum on, don't roll over onum..........:(

[Kev-o]

How about this? Now a new master cylinder and slave cylinder, great clutch pedal feel, BUT when i come to a stop at the lights i can not put it in to gear some times, i have to shut the truck off and start it in gear ( not great for the starter i'm sure ) and if i am backing up it's loading the clutch when i try to get it out of reverse? do you guy's think that it could be that i need to replace the clutch and pressure plate as well as the pivot fork and ball stud?

Thanks Kev-o

[Conflict]

Hi, maybe you guys can help me. I had my clutch all rebiult about 2 years ago by the local (Now Defunked) GMC Dealer. Within a week they had to replace the slave because it was leaking. Now 2 years later the slave empties about2 oz. of fluid when I carry small loads or my 17 foot motorboat and camper. It has happened a couple of times but it seems fine when I have no load. I do not have to travel more than a couple of miles before it gets hard to shift. Do I need another slave again. I hear they are plastic taboot.

[oilburnertoo]

How about this? Now a new master cylinder and slave cylinder, great clutch pedal feel, BUT when i come to a stop at the lights i can not put it in to gear some times, i have to shut the truck off and start it in gear ( not great for the starter i'm sure ) and if i am backing up it's loading the clutch when i try to get it out of reverse? do you guy's think that it could be that i need to replace the clutch and pressure plate as well as the pivot fork and ball stud?

Thanks Kev-o


If it was me I would replace the clutch assembly, the pivot ball and release fork, the pilot bushing [use the old style bronze bushing] not the new style roller bearing[they tend to lock up and disentigrate], the transmission front bearing retainer[T/O bearing rides on it and is most likely worn and groved up] and be done with it once and for all.

[a5150nut]

Hi, maybe you guys can help me. I had my clutch all rebiult about 2 years ago by the local (Now Defunked) GMC Dealer. Within a week they had to replace the slave because it was leaking. Now 2 years later the slave empties about2 oz. of fluid when I carry small loads or my 17 foot motorboat and camper. It has happened a couple of times but it seems fine when I have no load. I do not have to travel more than a couple of miles before it gets hard to shift. Do I need another slave again. I hear they are plastic taboot.

Welcome to TDP. Now for your problem. I know the 94 has an external plastic slave on it. But, I think 96 and up has the internal slave and not sure if it is still plastic. Can you find any signs of leaking?

[Conflict]

I checked under the truck and there does appear to have had some dot 3 type fluid dripping pretty much below the clutch housing. It is a 97 and I remember the dealship telling me that it was a plastic slave and that it was internal. Thanks for replying so quickly

[a5150nut]

I checked under the truck and there does appear to have had some dot 3 type fluid dripping pretty much below the clutch housing. It is a 97 and I remember the dealship telling me that it was a plastic slave and that it was internal. Thanks for replying so quickly

Not a problem. You will find some around here live on this site. I don't have any help to offer on the internal slave but just keep checking in here and someone will be along to help soon.:)

[johnanc]

I had similar trouble with clutch master cylinder failures, seemed it was because the pressure plate recently bought as part of a dual-mass to single-mass conversion was too stiff. After replacement of the clutch assembly with a LUK Rep-set (P/N 04-163) transmission working well. John

[Kev-o]

Well i finally tore into it and what a PAIN! When i pulled the tranny out from under the truck to inspect all areas, i found the input shaft had two small grooves in it, the throwout/release bearing was not great and had some bad wear areas where the spring like tabs from the clutch release fork had been trying to rub through, the release fork had a very bad wear pattern in it from the stud and the stud itself was in bad shape so the next thing to check was the bearing in the crank shaft (forgive me as i can not think of the name while i type this/brain fart?) but i could see it was a mess! So i need to pick up more parts in the morning and race to get it back together.

Thanks for all the input here guy's

Kev-o

[Kev-o]

One more thing! the lobe in the release bearing, is it supposed to be in a certain position?

[Kev-o]

I need input! I replaced everything i needed and put it back together and was bleeding the clutch and it got REAL tight? any suggestions ?

Thanks

Kev-o

[trbankii]

Searching for information... Looks like I'm in for some work (or more work).

When I bought the truck, the first time I went to look at it the seller went to pull it out and the clutch pedal went to the floor. The pressure line had gone out. He got it replaced and I bought the truck a few days later.

Coming home from work tonight, pedal goes to the floor when I went to shift to second pulling away from a stop sign. Luckily not in traffic so I drift to the side of the road and get out to take a look. Obvious trail of fluid on the street from under the passenger side of the truck - which is where the line broke the last time. Was able to limp it home two miles by starting off in second and creeping along.

Dark now, so I'm going to grab some dinner and then go out to see if I can tell whether it is just the line or something more.

Since someone else repaired it the last time, I cannot vouch for how well it was done. A bracket for the line was mentioned in an earlier post. Not sure if the line was routed correctly or if the bracket was used so it may just be a case of improper installation causing premature failure. But what mileage are people seeing before having to do the whole release fork/pivot ball/etc. replacement?

I'm hoping that it was just the pressure line and that I can throw another in there to buy me some time. Right now I'm stuck with the truck as my only vehicle and too much overtime to fit in dropping the trans to replace everything... We will see...

[JohnC]

Right now I'm stuck with the truck as my only vehicle and too much overtime to fit in dropping the trans to replace everything... We will see...


Time to learn to shift without the clutch...

;)

[trbankii]

That is how I got it home last night...

Although it worked, it wasn't exactly pretty. No grinding of gears, but I'm sure there were a couple people behind me that hated my guts...

Didn't get a chance to get out to look at things last night - dark and pouring rain by the time I had something to eat. Hopefully the weather will cooperate tonight so I can at least see what parts I need.

[trbankii]

Ok, got under the truck over the weekend to take a look - not the clutch line. The piece of the slave cylinder that the pin goes through was cracked and let the clutch line pop right out. Looking at it, I'm convinced that the seller buggered it up when he replaced the line. Another good reason on why I do my own work...

So placed the order for the parts through RockAuto and hope they will be here this week. Why the fook they made the slave out of plastic is a whole 'nuther matter... Say what you will about foreign vehicles, but at least my Toyota has a metal master and slave and a metal line that threads into each end...

[trbankii]

Figured that I'd give an update after a month here. Replaced the slave and things have been working fine. I'm still a bit wary about the whole plastic components issue, though...

Everything seems to shift smoothly and I'm trying to convince myself that it was just a matter of fourteen years of stress on plastic components - or that when the seller worked on clutch line he stressed the slave cylinder connection. We'll see what happens.

[ccatlett1984]

why dont you guys have flex lines made up and eleminate the vibration problem all together?

[trbankii]

I'm beginning to look at the options of swapping components. Part of the problem is that the master and slave cylinders are plastic and have a somewhat unique fitting for the lines that involves a retaining pin rather than typical hydraulic fittings. If I can find a master and slave that will work without serious fabrication work, I'll change everything out and have lines made up.