New Master Cylinder
May 30th, 2023, 05:45 PM
#1
Woodeye
Thread Starter
Join Date: Mar 2018
Location: Oklahoma
Posts: 28
New Master Cylinder
What could be more simple than a single reservoir Master Cylinder ? I can not get my NEW Master cylinder to build any pressure. Pedal goes straight to the floor with almost no resistance at all. Flushed system with new fluids. Can pump pedal to hearts content, goes to floor every time with no reduction of level in reservoir. This is on my 1962 Starfire with the Delco-Moraine Power Booster. I am missing something but darned if I know what it is. Any of you guys ever experence anything like this ? Thanks for any and all suggestions.
May 31st, 2023, 04:48 AM
#4
Registered User
Join Date: Jan 2010
Posts: 1,922
It possibly could be the seals went bad sitting for that long, and assuming it was a Delco, perhaps manufactured in the 60s, or even 70s it would almost be 50 years old.
While most of the master cylinders are tested in the factory, some aftermarkets are not, and as mentioned, shelf life may have something to do with performance. Dry seals will deteriorate over time. Even so, the seal material makes a difference, too along with shelf time. This is why NEW and OLD doesn't always mean problem-free.
While most of the master cylinders are tested in the factory, some aftermarkets are not, and as mentioned, shelf life may have something to do with performance. Dry seals will deteriorate over time. Even so, the seal material makes a difference, too along with shelf time. This is why NEW and OLD doesn't always mean problem-free.
May 31st, 2023, 07:43 AM
#6
Woodeye
Thread Starter
Join Date: Mar 2018
Location: Oklahoma
Posts: 28
TNSWT, inside the MC is one flat soft washer seal and the Cup. Both seem pliable
redoldsman, it is a new MC, Marketed by Raybestos.
69HO43, possible but they seem quiet pliable
oldcutlass, this is the old style Delco-Moraine system where the MC piston is part of the Brake Booster. So pedal, rod and piston. To get a different travel you use shims and manual says no more than 5. I am using 4 as that was what was there on disassembly. I think I am OK on this count.
I guess I will put all back together once again and bleed again. The Oldsmobile manual says to go in this order. LF, RF, LR and then RR wheel. This is a different order than I have used on other vehicles but the manual says this is the order. I thought maybe because it is a single reservoir and not a dual might be the difference. Any thoughts ?
Thanks to everyone trying to help.
redoldsman, it is a new MC, Marketed by Raybestos.
69HO43, possible but they seem quiet pliable
oldcutlass, this is the old style Delco-Moraine system where the MC piston is part of the Brake Booster. So pedal, rod and piston. To get a different travel you use shims and manual says no more than 5. I am using 4 as that was what was there on disassembly. I think I am OK on this count.
I guess I will put all back together once again and bleed again. The Oldsmobile manual says to go in this order. LF, RF, LR and then RR wheel. This is a different order than I have used on other vehicles but the manual says this is the order. I thought maybe because it is a single reservoir and not a dual might be the difference. Any thoughts ?
Thanks to everyone trying to help.
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