Clutch Issues? (Page 1/1)
rglasco101 AUG 19, 03:08 PM
I seem to have a issue with my 88gt 5 speed,
1. Clutch does not engage until it is almost to the floor
2. 1st and 2nd are very "tight" lots of pressure to get to the left all the way to select those 2 gears, but will go in
3. reverse grinds terribly, easier to turn the car off and put in reverse then start back up.

Clutch has been gravity and vacuum bled multiple times but no real improvement, is it a possible bad master or slave Cylinder? (1 & 3)
cables need adjusting for item 2?

Thanks everyone
Rob
Vintage-Nut AUG 19, 04:54 PM
Do you know how old your master/slave cylinders are?

Did you replace them recently?

If no, get new parts...

------------------
Original Owner of a Silver '88 GT
Under 'Production Refurbishment' @ 136k Miles

[This message has been edited by Vintage-Nut (edited 08-19-2025).]

Patrick AUG 19, 05:51 PM

quote
Originally posted by rglasco101:

Clutch does not engage until it is almost to the floor



"Engage"? Or disengage?

How high does your clutch pedal sit above the brake pedal at rest?

Can you shift into all gears just fine when the engine is not running?

Just so you know, this topic has been covered hundreds of times in this forum. All posts and threads dating back to 1999 are still accessible.
Dennis LaGrua AUG 19, 08:04 PM
.

[This message has been edited by Dennis LaGrua (edited 08-19-2025).]

Dennis LaGrua AUG 19, 08:46 PM
I would check:
1 If the clutch pedal is not bent (they often do bend)
2. If the master and slave cylinders are both functional (Fork moving when pedal depressed)
3. If the clutch fork itself is bent.

Since your system is 37 years old you may wish to rebuild the entire system.

------------------
" THE BLACK PARALYZER" -87GT 3800SC Series III engine, custom ZZP /Frozen Boost Intercooler setup, 3.4" Pulley, Northstar TB, LS1 MAF, 3" Spintech/Hedman Exhaust, P-log Manifold, Autolite 104's, MSD wires, Custom CAI, 4T65eHD w. custom axles, Champion Radiator, S10 Brake Booster, HP Tuners VCM Suite.
"THE COLUSSUS"
87GT - ALL OUT 3.4L Turbocharged engine, Garrett Hybrid Turbo, MSD ign., modified TH125H
" ON THE LOOSE WITHOUT THE JUICE "

rglasco101 AUG 20, 11:15 AM

quote
Originally posted by Patrick:

"Engage"? Or disengage?

How high does your clutch pedal sit above the brake pedal at rest?

Can you shift into all gears just fine when the engine is not running?

Just so you know, this topic has been covered hundreds of times in this forum. All posts and threads dating back to 1999 are still accessible.



yes, disengage, shifting to all gears is fine with engine off, 1st/2nd still a little tight, pedal is about even with the brake, just doesn't seem to dao anything till it almost bottoms out
Larryinkc AUG 20, 11:50 AM
Some good clutch info from V8 Archie, I have used his method and it worked good for me.

Archisms
http://www.v8archie.com/v8Archie/ToC6.htm

Rodney has dual seal slave pistons that might help also.

http://rodneydickman.com/pr....php?products_id=288

Clutch bleeding prodeedure
You can do it your way, But this method always works for me.
After checking to be sure there are no leaks in the Clutch Hydraulic system.
Complete ALL of the following steps before test driving the car:
1) Install a helper in the drivers seat to push in and let out the clutch pedal on command.
2) Remove the cover from the Master Cylinder reservoir.
3) Top off fluid in the reservoir.
4) During the course of this procedure DO NOT allow the "helper" to "pump" the pedal. The "helper" is to depress and release the pedal on command only, DO NOT PUMP THE PEDAL. (See theory below)
5) You will be opening and closing the bleed screw on the slave cylinder as instructed below. CAUTION: During this procedure protect your eyes from squirting brake fluid.
6) (Helper) Press clutch pedal in fully and hold.
7) (You) Open the bleed screw to allow fluid to escape.
8) (You) Close bleed screw.
9) (Helper) Release pedal completely
10) (You) Top off fluid in reservoir.
11) Repeat steps #6 thru #10 no less than 5 times before going to #12 below. NO PUMPING!
12) You have now bled the Master Cylinder and the hydraulic line. YOU ARE NOT DONE YET!!!!! We must now bleed the Slave cylinder. (This is what the manual doesn’t tell you)
13) With no further action to be done with the clutch pedal, you can no remove the "helper" from the drivers seat and have him (her/it) help you do the following.
14) After topping off the Master Cylinder, completely remove the bleed screw from the slave cylinder.
15) Have the "helper" stand at the ready with the bleed screw and the appropriate wrench for installing the bleed screw.
16) PROTECT YOUR EYES!
17) With the bleed screw removed. With both hands grab the push rod coming out of the slave cylinder and push it into the slave cylinder as far as it will go AND HOLD it in.
18) Your "helper" will now install and tighten the bleed screw while you hold the plunger in.
19) When bleed screw is tight release the rod and as it comes out guide it into the proper position on the clutch arm.
20) Top off the Reservoir and the job is complete.

Theory:
Why do I insist that you REMOVE the bleed screw when pushing the plunger in on the slave cylinder? This is simple hydraulics. Fluid or air will always go the direction of least resistance. When you are pushing the rod into the slave cylinder you will find that it is impossible to push it in at a slowly and steadily pace. If you push it in too fast with the bleed screw still in and just unscrewed a few turns some of the brake fluid and/or air in the slave cylinder will go back up the hydraulic line that you just bled, thus necessating your starting over.
When bleeding your clutch....The biggest mistake or miss-conception a person can make is to pump the pedal.
The clutch Hyd. system, unlike the brake Hyd. system SHOULD NOT BE PUMPED. The only thing that happens when you "pump" the clutch is that you make any large air bubbles in the hydraulic system into a bunch of small air bubbles. BTW these small air bubbles are harder to bleed out than larger bubbles.
You cannot "pump up" a clutch. If you have to "pump up" the clutch to make a shift then you have a leak and you can bleed the system a dozen times to no avail.
On the clutch, think about it now, if you could "pump-up" the clutch wouldn't the T.O. Bearing tend to invert the clutch diaphragm and travel toward the engine until it met up with something solid like the flywheel. On a braking system, when you "pump-up" the brakes you force the brake pads into the rotor until the line pressure builds up enough that the resistance you feel when pumping the pedal increases. Further, as you press harder and harder on the brake pedal the pads just increase their pressure on the rotors.
GM Thought this through when they designed the system. To avoid "pumping up" the clutch hyd. system, GM put in a small bleed back hole in the master cylinder. (BTW not an original idea, all Hyd. clutches have it) This bleed back hole relieves line pressure every time the pedal is at the top of the stroke. Didn't you notice when you "pumped up" the clutch pedal that it doesn’t firm-up like the brake pedal does?
The only thing you accomplish when "pumping up" the clutch pedal is to take any air bubbles that are in the system and atomize them into smaller air bubbles, thus making the problem worse. Remember when you were at the soda shop, as a kid, and your parents kept giving you hell about playing with you soda and straw? Same theory here! The more you move that soda through the straw the smaller the air bubbles become.
BTW the "hand pumps" work ok but I’ve never needed to buy one yet. With the hand pumps you still need to ensure that the slave cylinder gets completely bled.
v8archie

[This message has been edited by Larryinkc (edited 08-20-2025).]

Dennis LaGrua AUG 28, 03:15 PM

quote
Originally posted by Larryinkc:

Some good clutch info from V8 Archie, I have used his method and it worked good for me.

Archisms
http://www.v8archie.com/v8Archie/ToC6.htm

Rodney has dual seal slave pistons that might help also.

http://rodneydickman.com/pr....php?products_id=288

Clutch bleeding prodeedure
You can do it your way, But this method always works for me.
After checking to be sure there are no leaks in the Clutch Hydraulic system.
Complete ALL of the following steps before test driving the car:
1) Install a helper in the drivers seat to push in and let out the clutch pedal on command.
2) Remove the cover from the Master Cylinder reservoir.
3) Top off fluid in the reservoir.
4) During the course of this procedure DO NOT allow the "helper" to "pump" the pedal. The "helper" is to depress and release the pedal on command only, DO NOT PUMP THE PEDAL. (See theory below)
5) You will be opening and closing the bleed screw on the slave cylinder as instructed below. CAUTION: During this procedure protect your eyes from squirting brake fluid.
6) (Helper) Press clutch pedal in fully and hold.
7) (You) Open the bleed screw to allow fluid to escape.
8) (You) Close bleed screw.
9) (Helper) Release pedal completely
10) (You) Top off fluid in reservoir.
11) Repeat steps #6 thru #10 no less than 5 times before going to #12 below. NO PUMPING!
12) You have now bled the Master Cylinder and the hydraulic line. YOU ARE NOT DONE YET!!!!! We must now bleed the Slave cylinder. (This is what the manual doesn’t tell you)
13) With no further action to be done with the clutch pedal, you can no remove the "helper" from the drivers seat and have him (her/it) help you do the following.
14) After topping off the Master Cylinder, completely remove the bleed screw from the slave cylinder.
15) Have the "helper" stand at the ready with the bleed screw and the appropriate wrench for installing the bleed screw.
16) PROTECT YOUR EYES!
17) With the bleed screw removed. With both hands grab the push rod coming out of the slave cylinder and push it into the slave cylinder as far as it will go AND HOLD it in.
18) Your "helper" will now install and tighten the bleed screw while you hold the plunger in.
19) When bleed screw is tight release the rod and as it comes out guide it into the proper position on the clutch arm.
20) Top off the Reservoir and the job is complete.

Theory:
Why do I insist that you REMOVE the bleed screw when pushing the plunger in on the slave cylinder? This is simple hydraulics. Fluid or air will always go the direction of least resistance. When you are pushing the rod into the slave cylinder you will find that it is impossible to push it in at a slowly and steadily pace. If you push it in too fast with the bleed screw still in and just unscrewed a few turns some of the brake fluid and/or air in the slave cylinder will go back up the hydraulic line that you just bled, thus necessating your starting over.
When bleeding your clutch....The biggest mistake or miss-conception a person can make is to pump the pedal.
The clutch Hyd. system, unlike the brake Hyd. system SHOULD NOT BE PUMPED. The only thing that happens when you "pump" the clutch is that you make any large air bubbles in the hydraulic system into a bunch of small air bubbles. BTW these small air bubbles are harder to bleed out than larger bubbles.
You cannot "pump up" a clutch. If you have to "pump up" the clutch to make a shift then you have a leak and you can bleed the system a dozen times to no avail.
On the clutch, think about it now, if you could "pump-up" the clutch wouldn't the T.O. Bearing tend to invert the clutch diaphragm and travel toward the engine until it met up with something solid like the flywheel. On a braking system, when you "pump-up" the brakes you force the brake pads into the rotor until the line pressure builds up enough that the resistance you feel when pumping the pedal increases. Further, as you press harder and harder on the brake pedal the pads just increase their pressure on the rotors.
GM Thought this through when they designed the system. To avoid "pumping up" the clutch hyd. system, GM put in a small bleed back hole in the master cylinder. (BTW not an original idea, all Hyd. clutches have it) This bleed back hole relieves line pressure every time the pedal is at the top of the stroke. Didn't you notice when you "pumped up" the clutch pedal that it doesn’t firm-up like the brake pedal does?
The only thing you accomplish when "pumping up" the clutch pedal is to take any air bubbles that are in the system and atomize them into smaller air bubbles, thus making the problem worse. Remember when you were at the soda shop, as a kid, and your parents kept giving you hell about playing with you soda and straw? Same theory here! The more you move that soda through the straw the smaller the air bubbles become.
BTW the "hand pumps" work ok but I’ve never needed to buy one yet. With the hand pumps you still need to ensure that the slave cylinder gets completely bled.
v8archie



You don't need a long involved complex 2 man procedure to bleed the clutch hydraulic system. The above system that was described is just a big waste of time. All you need is a vacuum brake bleeder tool attached to the slave cylinder bleeder screw.. Just put heavy silicone grease on the bleeder screw threads fill the system with brake fluid open the bleeder screw and pump until no bubbles are seen in the vacuum line. Then close the bleeder screw-all a simple one man job done in 10 minutes. Have done this several times on customer cars in the past and the clutch action was perfect.

------------------
" THE BLACK PARALYZER" -87GT 3800SC Series III engine, custom ZZP /Frozen Boost Intercooler setup, 3.4" Pulley, Northstar TB, LS1 MAF, 3" Spintech/Hedman Exhaust, P-log Manifold, Autolite 104's, MSD wires, Custom CAI, 4T65eHD w. custom axles, Champion Radiator, S10 Brake Booster, HP Tuners VCM Suite.
"THE COLUSSUS"
87GT - ALL OUT 3.4L Turbocharged engine, Garrett Hybrid Turbo, MSD ign., modified TH125H
" ON THE LOOSE WITHOUT THE JUICE "

Patrick AUG 28, 03:40 PM

quote
Originally posted by rglasco101:

yes, disengage, shifting to all gears is fine with engine off, 1st/2nd still a little tight, pedal is about even with the brake, just doesn't seem to dao anything till it almost bottoms out



You may have other issues as well (such as air in the hydraulics), but the clutch pedal is supposed to sit about an inch above the brake pedal at rest. I suspect your clutch pedal and/or the banjo is bent. Something as simple as an adjustable banjo (to enable full throw) may be enough to rectify your shifting problem.