Super tight clutch issue…. (1 Viewer)

[charliemeyer007]

Kits are cheap for MC and SC. Proper adjustment/bleeding is nearly free for a little time

 

[pb4ugo]

Thanks. I bled the clutch a few months ago and the fluid in it was super dirty. The fluid seems pretty clean still. I did have my daughter push in the clutch today while I was underneath to make sure the slave was moving the clutch back and forth and it was. Maybe it isn’t pushing it far enough bc of the seals/pressure and that could be the issue maybe?

I’ll re-bleed this week and see if that makes a difference. If it doesn’t then maybe time to replace the MC and SC.

If the hydraulics arent leaking your parts are probably OK. If you adjust the clutch per the fsm, it will insure you are getting maximum travel out of the master and slave cylinder. Adjust pedal height and pedal free play. Then adjust the rod at the slave. You can bleed gallons thru it, If the adjustments are off bleeding won't help. If the problem still exist, then maybe you'll need to rebuild or replace parts.

 

[Mark Jennings]

I just found this when I googled up Clutch Drag, read and enjoy……and comment on the ‘Rev and Launch Limiter’

CLUTCH DRAG IS SERIOUS​

Improper clutch adjustment, or dragging clutch assembly, will destroy your new unit. Damaged synchros due to improper clutch engagement will VOID YOUR WARRANTY!! If we receive the unit back damaged due to the clutch, we will know! 95% of all transmission failures are caused by clutch related issues. It is terribly important that the vehicle does not have clutch drag. To test is simple:

• With the vehicle running, disengage the e-brake so it can roll.
• Push the clutch pedal all the way to the floor and hold it there.
• Turn off your launch limiter so the engine can hit the rev limiter. You MUST DO THIS!! If you do not, then there is no point in performing this test.
• Shift the car into 1st gear.
• Rev the engine up, while the clutch pedal is depressed all the way to the floor, until you feel the car start to move forward.

If the vehicle moves forward below the rev limiter, your clutch is dragging. Do not drive until the problem is fixed, or your synchros will be ruined! Unit will also be hard to shift, so DON’T DRIVE OR FORCE IT INTO GEAR! If everything is correct, the vehicle will not move. If the vehicle moves forward or is hard to shift, check each of the following:

 

[pb4ugo]

It happens in every single gear. I should have been more clear about that. It didn’t seem to get better, but I only drove it a total of around 8 miles round trip.

When the op mentions the shifting problem happens in every gear, then it's not likely a trans problem. I think it's an adjustment or hydraulic problem.

 

[sleepycruiser]

So trying to adjust the clutch pedal. It is about at 7.25” to the top of the pedal, which according to the FSM page is about 1” too short. However, it is the same height as the brake pedal (which I read they should be similar), but when I look at the bolt to adjust the pedal higher the pedal is maxed out against the part where the adjustment bolt is…so there is no way to adjust the clutch pedal higher, unless I am misreading how to make the adjustment.

Excuse the electrical tape on the stop bolt…using it as a ground.

 

[charliemeyer007]

My clutch pedal was set down about 2" by the 6'5" PO when he put on the hardtop. With rag top door he could bow it out enough to shift, not so with hard top door. I'm only 6'2" but it works for me so I never changed it.

 

[65swb45]

The more relevant question is how far you can push it down before you feel it making pressure inside the MC? If you’re not familiar with how the hydraulic system works, you might have to temporarily remove the return spring in order to make that evaluation.

 

[pb4ugo]

So trying to adjust the clutch pedal. It is about at 7.25” to the top of the pedal, which according to the FSM page is about 1” too short. However, it is the same height as the brake pedal (which I read they should be similar), but when I look at the bolt to adjust the pedal higher the pedal is maxed out against the part where the adjustment bolt is…so there is no way to adjust the clutch pedal higher, unless I am misreading how to make the adjustment.

Excuse the electrical tape on the stop bolt…using it as a ground.

View attachment 3779263

View attachment 3779264

The fsm page I posted I'd from a copyright 1974. 1964 might have a different spec.
As Mark mentioned your freeplay might be off. I found having someone watch the slave for when it starts moving while you start pushing on the pedal. I found using my hand to push the pedal because the adjustment is slight. Once height and freeplay is adjusted you can adjust the rod at the slave. Make sure the slave piston is fully retracted in the bore. Push it in, then adjust the rod. Be sure to use a return spring when your done.

 

[Mark Jennings]

Attached is a cut from early FSM, calls for 9 inches of pedal…since this is a 4 speed upgrade, no telling what it should be….@Greebean recently did a 4 speed upgrade, he may be able to answer.

 

[sleepycruiser]

It feels like about 1” of free play. I measured how the FSM page above shows and it is right at 9”, although as mentioned, since it is now a 4 speed who knows what it should be.

I’ll do some research on how to adjust the slave and see if I can get anything dialed in.

 

[65swb45]

Putting aside the fsm for a moment, trying adjusting the MC pushrod as close to zero as possible without the rod being in danger of falling out of the clevis long enough to take a test drive and see if it resolves the issue.

 

[65swb45]

Also note that in two cases over the last four decades I could not get a proper adjustment out of the factory components after doing a 4 speed swap.

In both instances I took a piece of round stock and made a longer pushrod for the slave. It’s not rocket science.

 

[pb4ugo]

1" freeplay or an 1" b4 you feel resistance? They're different. This adjustment insures your getting full stroke of the master. I adjust it when the piston is seated in the slave bore and when the piston/rod starts to move. I push the pedal by hand. Freeplay adjustment is the master to pedal rod. Then adjust the rod at the slave. I swapped a 3 to 4 speed in my 72 with no issues or adjustments except for the rod. These adjustments should get you the maximum stroke with what you have.

 

[sleepycruiser]

1" freeplay or an 1" b4 you feel resistance? They're different. This adjustment insures your getting full stroke of the master. I adjust it when the piston is seated in the slave bore and when the piston/rod starts to move. I push the pedal by hand. Freeplay adjustment is the master to pedal rod. Then adjust the rod at the slave. I swapped a 3 to 4 speed in my 72 with no issues or adjustments except for the rod. These adjustments should get you the maximum stroke with what you have.

1” before I felt resistance. Thanks for the info. I’ll see what I can in the next few days to get the clutch dialed in.

 

[Blue77FJ40]

I had my clutch master blow out on the way home from a trip, no pressure and no leakage, so leakage is not always a given. Had to triple/quadruple/pentiple clutch to build up enough pressure to shift, making stop lights a bear. Once I got home, I ordred and and installed a new OEM clutch master and slave - problem solved.

When you replace, buy the clutch master and slave at the same time. OEM only. Don't screw around with aftermarket unless it's a high end japanese company. Also, I'd suggest having a spare slave on hand. I had one go out an a trail ride and just swapped in a new one that I carry on board in a small action packer. I use a bottle with a one way valve and connections to the bleeder screw that I picked up at Phoenix Brake systems.

One Man Brake Bleeder Capture and Refill Bottle / Container

The one man brake bleeder bottle has all the bells and whistles to make your next brake bleeding job a less messy, super fast project. First, use the 20 lb heavy duty magnet to hang your capture bottle close to the caliper. Second, press the quick fitting over the top of the bleed screw and...

brakebleeder.com

Makes bleeding by myself a snap. The bottle has a cord with with a magnet to hold bottle vertical and I sit on a low mechanic's cart using a long rod to press the clutch so that I can watch the clear tubing to the bottle until no bubbles show. Once you get an idea of how many pumps it takes to leave the reservoir about 1/4 full, then refill so as not to introduce air. Always bleed from furthest from master to closest. I always keep a few bottles of brake fluid, to permit full flushes if necessary.

I have their hand pump bleeder, but usually just use the bottle.

 

[sleepycruiser]

I had my clutch master blow out on the way home from a trip, no pressure and no leakage, so leakage is not always a given. Had to triple/quadruple/pentiple clutch to build up enough pressure to shift, making stop lights a bear. Once I got home, I ordred and and installed a new OEM clutch master and slave - problem solved.

When you replace, buy the clutch master and slave at the same time. OEM only. Don't screw around with aftermarket unless it's a high end japanese company. Also, I'd suggest having a spare slave on hand. I had one go out an a trail ride and just swapped in a new one that I carry on board in a small action packer. I use a bottle with a one way valve and connections to the bleeder screw that I picked up at Phoenix Brake systems.

One Man Brake Bleeder Capture and Refill Bottle / Container

The one man brake bleeder bottle has all the bells and whistles to make your next brake bleeding job a less messy, super fast project. First, use the 20 lb heavy duty magnet to hang your capture bottle close to the caliper. Second, press the quick fitting over the top of the bleed screw and...

brakebleeder.com

Makes bleeding by myself a snap. The bottle has a cord with with a magnet to hold bottle vertical and I sit on a low mechanic's cart using a long rod to press the clutch so that I can watch the clear tubing to the bottle until no bubbles show. Once you get an idea of how many pumps it takes to leave the reservoir about 1/4 full, then refill so as not to introduce air. Always bleed from furthest from master to closest. I always keep a few bottles of brake fluid, to permit full flushes if necessary.

I have their hand pump bleeder, but usually just use the bottle.

Thanks for that info. I found some Aisin master cylinders and slave cylinders. Mine don’t have any leaks, but as you mentioned that might not be a symptom of failure. I’m going to try to adjust the slave first and if that doesn’t work I’m going to replace both and go from there.

Thanks on the tip for the bleeder…I normally just put a pan under it…but with that I’d be able to see that all air bubbles are out. Last time I just did a gravity bleed for several seconds.