It appears that my slave cylinder & master cylinder are original to the 89 vette. I’ve read the FSM process but can anyone add to this since I’ve not done it before? Are there tips & tricks?

I’m also looking at replacing the Clutch Slave Cylinder & the Master Cylinder in the future & would like to find replacements. Looking around it seems like they aren’t the easiest things to find as GM & most aftermarket manufacturers have stopped making them. Is there a preferred manufacturer other than GM which is recommended today? Finally it seems like there is quite the push to replace these units before they “go bad”, is that really necessary?

 

before replacing anything, bleed properly and thoroughly.

what i do, ymmv: use extensions and a 3/8 drive to remove slave. rotate and support (i use bungies/zip straps to secure) slave so the bleeder nipple is both facing up, and also the hightest elevation.

i suck all the dirty master fluid out, and replace with fresh, in my case, motul 600 or 660.

then i connect a clear nylon hose to the nipple, i use a small zip strap around the nipple to add clamping force around the nylon hose.

i then pump the fluid out using the one man bleed method. i do this also for brakes. search youtube and watch chris fix's video on it. and keep filling the master up so you do not ever run out of air in the master reservoir. it is a VERY VERY SMALL reservoir. the purpose here is to just displace all the dirty fluid with clean fluid you keep filling into the master reservoir. the dirty stuff is pumped out into the bottle (again, watch chris fix vid).

THEN, once i know i have clean fluid, i go after any residual trapped air. i take the hose that was placed into the bottle (per chris fix video) and i run it back up to the clutch master cylinder.

Now you are circulating the fluid, pumping it with the clutch pedal. you can get some good velocity up and any bubbles that stay trapped can be allowed to go free and will rise to the top of the master.

That is how i do it. if it doesn't work right after doing that, then you for sure need a replacement master and slave.

purchasing and new master and slave to have on hand is a good idea. try to get non-remanned.

 

No nipple just the cap & when that’s off it’s a flat top. (Don’t ask me why but the original owner had it undercoated!)

 

Use a power bleeder, takes the guess work out of it. They used to be a shop only expensive item, but can be purchased cheap at harbor freight, or possibly rented from AutoZone etc. Or if you have a midas, meineke, etc near you they used to charge a flat rate for bleeding stuff like this. Or any transmission shop , it shouldn't cost much. I flushed out the system and used dot4, supposed to have a higher boiling point.

 

ill be checking out the power bleeder thnx.

op u should have a bleeder like this :

 

I’m pretty sure it doesn’t come with a bleeder screw attached. At least that’s my interpretation from the FSM where they talk about using a screw extractor;

 

odd. i purchased a cast but new slave from my local parts shop and it came with a nipple. messy job without the hose attached!

i also see the mention of not recirculating fluid! maybe what i do with circulating back into the master reservoir is bad?

 

I’ve not seen the other end of the slave cylinder. What’s it look like? Is there any issues putting it back in place after removal? If not I’ll have to pull it & see if I can put some kinda of an extractor tool in to remove it then get a nipple that will fit or weld a nut on the end…. Something different than what’s there.

 

So I have an 89 project car on my Lyft right now. Went out to look at the slave cylinder. I knew it was missing a stud, but low and behold it looks like it’s the same as yours. So I guess I’m along for the ride to see what you do! My 1990 and my 1991 all have bleeder screws.

 

My suggestion is to replace both the master and slave, and convert to the later SS braided line. The line will be the most expensive piece. There is no need to break off the bleeder on later designs. I used Luk brand master/slave and they are very inexpensive.

Also, if you aren’t flushing but just trying to bleed it..swap the fluid in the reservoir and pump the clutch…it self bleeds.

If you change everything out bench bleed the slave, pour fluid into the master and connect the hose while the fluid is coming out…then fill the master and pump the daylights out of the pedal/use the ranger method.

Unless you are trying to flush old fluid from the system there is no reason to use the bleeder. In fact, if the bleeder screw does not have Teflon tape you may introduce air instead of remove it.

 

I wish I could do the pump (ranger) method of flushing fluid but it doesn’t work on the 89 system.

 

Replace the master and slave cylinder. Don't fool with bleeding till the new ones are on. You will be wasting your time. It's not that hard of a job.

Bleeding was actually the hardest part because there is no fracking room to work...

 

Works fine on my '89.

That's the only way I do it. FAST, EASY, Clean.

 

Agreed... I don't see why the system would behave any differently on an 89... I think attempting to bleed it using the bleed screw can make things *worse* and frustrate the hell out people. Best to use the bleed screw only for when you are flushing the fluid....and I would pre-emptively put teflon on the threads prior to new slave install... And again, with a new slave cylinder, bench bleed it!

This is my experience (ranger/pumping works fine) both when I had known air in the system due to a master leak, and after complete system replacement (line and both cylinders).

 

Tom, is yours the same as my original unit? If it is it makes me wonder why mine doesn’t work with the ranger method as I tried it twice? It definitely concerns me as well. I will have to get a set (master & slave) ordered up & just replace them both very soon. I definitely don’t want my old slave or master to be malfunctioning & causing problems.

This morning I picked up the VSS (vehicle speed sensor) I had ordered to use on my 89 vette ZF tranny. I had a code 24 for the VSS & the speedometer only showed a “0” on my dash during my 1st test drive last week. I wasn’t able to find an exact replacement VSS but I’d read somewhere that the later (1992-96) VSS will fit in my ZF tranny but has a different connector. To test the new VSS I chucked up the end of it in my drill then connected a multi meter to the plug end prongs of the VSS on AC mode & gently spun it &I got a reading which went up with speed. Next I figured I’d pull the original one & test it to make sure it’s bad before I cut off the old pigtail & wire up the new one.

 

I can take a pic when I get home tonight and post it up.

 

Thanks Tom I really appreciate it!

In case anyone is curious about the VSS replacement…. I just pulled my old VSS & out gushed 1/4-1/2 cup of trans fluid. Naturally most of it missed my pan but surprisingly I didn’t wear it!

I put the later model VSS in place after putting the gear back on it. Hopefully it went on correctly because with all the fluid mess the gear fell off before I could see which way it went on the VSS.

I tested the new VSS with a multi meter before I put it in & got an AC reading as I spun the end of the VSS with the drill. I repeated this with the old unit & got no reading. So it’s a definitive that the old VSS was bad! Now I’ve gotta try to make sure the new one is completely & correctly seated then fire her up & spin the wheels to see if the dash shows a speed. 🤞🏻

 

VSS install completed & speedometer accurate up to 35 mph. I couldn’t get over that since she was having surging & chugging so I turned her around before I even got out of the neighborhood. On to the next repair…


New 1992 Vehicle Speed Sensor,


Seems to fit properly.


Old pigtail on left, new on right. I cut off the old one & soldered the new one on; purple wires together then yellow & black together.

 

'89 slave...

 

Sorry for the late reply but I’ve been driving it a little as I work on things. I’ve noticed that after I change the fluid in the reservoir it will dirty up again. So my plan is to just keep replacing the fluid little by little…