Master cylinder for c8a

[gjamo]

I have seen on of these G506 cylinders used but you need to delete
the original mounting bracket.

https://www.chevsofthe40s.com/detail...2dOcbBkI5LEy68

[Grant Bowker]

I can't find it right away bit there is at least one post (with photo) of a bracket made by Barry Churcher that fit between the original mount and a master cylinder similar to that mentioned by GJamo.
If you can find an original (even one that is pitted so that it is unusable) consider getting it sleeved with either stainless steel or brass. Many people have reported success (only a few report leakage between the sleeve and the original metal).


On edit, this http://www.mapleleafup.net/forums/sh...ghlight=master is not the thread I was thinking of but is another approach Barry has used...

[rob love]

If the external dimensions of the new master cylinder are ok, could you not get a machine shop to bore it out to 1-1/4 and install a rebuild kit?



At work, I made an adapter and installed a Ford master cylinder in place of the chev in a couple of instances.

[Grant Bowker]

Originally Posted by rob love

If the external dimensions of the new master cylinder are ok, could you not get a machine shop to bore it out to 1-1/4 and install a rebuild kit?

Without measuring the cylinder, my concern about overboring the master cylinder would be the small passage vertically into the fluid reservoir. Most masters I've seen have a larger diameter dimple cast in the base of the fluid reservoir and then a smaller hole drilled into the cylinder. If the overbore extended the working cylinder into the larger part of the hole to the reservoir, would the larger hole risk damaging the rubber cup? You might also need to redo the clip-in cap at the pushrod end of the cylinder depending on how much material remains for it to seat against. I'm not saying it can't be done, just things to check....

[Harry Moon]

Well i bought one of those Argentine master cylinders and put it on my C60L during restoration. Bled the brakes and everything worked fine or so I thought. Once the rest was put together and had the power booster on and actually used them, after a couple of brake applications the brakes went mushy. So bleed each wheel, remove drums to make sure no leaks etc. Damned if it wasnt the master cylinder. worst machining I've ever seen in a new part and dangerous the day it was put in a box.
The casting had a tapped and threaded hole near the base, it actually entered into the side wall of the cylinder. as you activated the brake the seal passed over this hole and cut off moon shaped slices off of the seal resulting in total loss of brake pressure. upon further inspection nothing was right about the machining, off centre. If you can't get the original resleeved try a later side mount with a fabricated bracket.

[Hanno Spoelstra]

Bonjour Serge,

As you noted the master cylinder you have has a smaller bore than the one normally fitted to the C8A. Thus, for the same amount of brake pedal pressure, a higher pressure will build up in the brake system. I think with a cylinder of 1" diameter you risk locking up the brakes when applying normal brake pedal pressure. I would say it would be better to fit a brake cylinder with the correct diameter of 1.25"

See the thread Replacement Chevrolet master cylinder for the thread Grant referred to.

Originally Posted by Grant Bowker

I can't find it right away bit there is at least one post (with photo) of a bracket made by Barry Churcher that fit between the original mount and a master cylinder similar to that mentioned by GJamo.
If you can find an original (even one that is pitted so that it is unusable) consider getting it sleeved with either stainless steel or brass. Many people have reported success (only a few report leakage between the sleeve and the original metal).