Fabio421

My clutch master cyl. saga continues. I have the new master in and the system bled but the clutch still doesn't work properly. The clutch never fully disengages. Comparing the full travel of the old master to the new one, there is a 3/4" difference. The new one bottoms out 3/4" sooner than the old one. That means that the slave isn't getting the same volume of fluid as it did in the past. Has anyone had this happen to them? I think we have the wrong master. It looks the same and it has the correct # on the box but it's got to be wrong.

Say something to keep me from having to pull this thing out again. Please!!! I'm desperate.

Thanks

nosnow

If you have the old master check the rod lengths. I remember there was an issue with some aftermarket parts in the past. Otherwise there is an air bubble in the master. Bleeding the clutch system is one of my least favorite jobs.

Mrmerlin

I think there are different length push rods for the slave, check you new/ old rod length, you may be able to check the diameter of the new /old master by removing the bellows. Also check the clutch pivot bushing on the top of the bell housing is in place

Fabio421

Nope, rod lengths are identical. The travel is shorter. You actually feel the piston bottom out, but it bottoms out earlier ( by 3/4" ) than the old one.

Thanks for the response.

Anyone else?

brutus

They changed how the return spring inside the master is located. The end of the piston is turned down and the spring fits over that piece but it is longer and that is what bottoms out and limits the travel. Take both apart and the difference is clear. You can grind off part of that extra length and get more stroke.

ROG100

The MC you have is good 79 through 95. Does the car have the 9" or 10" booster?
There is a different MC for the 78 cars. You may need the earlier MC.

Dennis Wilson

Have you adjusted the clutch pedal/rod like explained on page 30-1 in the WSM? The new rod/MC may be different lenghts so adjustment would be necessary.

Dennis

Fabio421

Thats good to know. maybe we can make what we have work.

I'll have to check the dia. of the booster. Is the larger booster for the 78 build cars? If so, that may explain why I had such a bear of a problem getting the master past the booster. I'm thinking that this may be a 78 build car billed as a 79.

Yes. That has been done. A few times.




Thanks for the input guys. I will be sure to post what I find in the morning so that others can learn from my problems.

Mrmerlin

IIRC the booster was replaced before you got the car and its a differnt size than the original

ROG100

The 9" booster was used in the earlier cars.
The 10" on the later cars.
You see size does matter 8>)

Dennis Wilson

I may have lost it, but I can't see how the size of the brake booster affects the operation of the clutch master cylinder? Did it cause a change to the location of the clutch MC?

Dennis

Mrmerlin

Dennis, it effects the removal of the clutch master....... this was mentined in another thread. anyway with the bigger 10 in booster installed its about impossible to follow the directions for removal of the whole clutch system from the car

Fabio421

Ok guys. The car is back on the road. We took the master cyl. apart and compared the two pistons and springs. As Brutus posted, the piston is made differently. It has a spring guide built onto it. The spring in the new one is also longer and has a thicker compressed thickness. We ended up machining off most of the spring guide and using the shorter spring to gain our travel that we lost. It worked like a charm. I will post a picture later.

Thanks again for everyones help.

ROG100

Dennis,
The size of the brake booster is a visual idication of whether you need the early or late style MC.
Roger

Dennis Wilson

Roger,

I'm still confused. Do you actually mean the size of the BRAKE BOOSTER is a visual indication of whether you need the early or late style CLUTCH MC? If so, that would make sense.

Thanks,

Dennis