Clutch Master Is In. Why Is The Travel 3/4" Shorter Than The Old One?
#1
Man of many SIGs
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Clutch Master Is In. Why Is The Travel 3/4" Shorter Than The Old One?
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
Say something to keep me from having to pull this thing out again. Please!!! I'm desperate.
Thanks
#2
Rennlist Member
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.
#3
Team Owner
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
#4
Man of many SIGs
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Thanks for the response.
Anyone else?
#5
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.
#6
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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.
There is a different MC for the 78 cars. You may need the earlier MC.
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Does it have the "Do It Yourself" manual transmission, or the superior "Fully Equipped by Porsche" Automatic Transmission? George Layton March 2014
928 Owners are ".....a secret sect of quietly assured Porsche pragmatists who in near anonymity appreciate the prodigious, easy going prowess of the 928."
Does it have the "Do It Yourself" manual transmission, or the superior "Fully Equipped by Porsche" Automatic Transmission? George Layton March 2014
928 Owners are ".....a secret sect of quietly assured Porsche pragmatists who in near anonymity appreciate the prodigious, easy going prowess of the 928."
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#8
Man of many SIGs
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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.
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.
#9
Team Owner
IIRC the booster was replaced before you got the car and its a differnt size than the original
#11
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
Dennis
#12
Team Owner
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
#13
Man of many SIGs
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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.
Thanks again for everyones help.
#14
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Dennis,
The size of the brake booster is a visual idication of whether you need the early or late style MC.
Roger
The size of the brake booster is a visual idication of whether you need the early or late style MC.
Roger
Last edited by ROG100; 10-06-2008 at 09:45 AM.
#15
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