I think I need a brake master cylinder
Thread Starter
Melting Slicks
Joined: Feb 2005
Posts: 3,472
Likes: 43
From: Auburn MA
I think I need a brake master cylinder
I replaced my booster a couple years ago because a hole melted in it and ever since I put the replacement booster in it the brake pedal has never felt the same. Before it was nice and firm and now it feels soft without as much response and it doesn't take much effort to put it to the floor. I still have good brakes and no leaks but I am wondering if the master is leaking internally. Is there a way I can diagnose if I need a master. I have replaced and bled the brake fluid with no change in pedal feel as well. Now I notice there are several Master cylinders for sale, my master has a separate line on the left of the reservoir which I believe goes directly to the ABS pump. Is there a specific part number i should get?
Thread Starter
Melting Slicks
Joined: Feb 2005
Posts: 3,472
Likes: 43
From: Auburn MA
no I dont see the level dropping and I dont see any leaks. How do you diagnose a bad brake master cylinder and where can I find a suitable replacement. Because everything i see in Ecklers, Zip Corvette, Corvette Central, Parts Geek, Amazon or any other place doesn't seem like they match (judging by the photo) what is on the car. I can't seem to find any brake master cylinders that have the fitting on the brake reservoir for the ABS pump. I also see where I need to know the size of brake fluid level sensor too and how that can be in two different sizes.
Drifting
Joined: Sep 2022
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From: Liberty, SC
2023 C4 of the Year Finalist - Unmodified
What I was getting to is that if the level isn't dropping you don't likely have a leak anywhere. Which would also mean your master cylinder may not be leaking internally. I'd want to think that you just need a good fluid flush and bleed (again).
If you're sure though, I don't know where I'd point you for a new master cylinder. There are plenty of threads where folks have replaced them. Maybe one of them mentioned where it came from too?
If you're sure though, I don't know where I'd point you for a new master cylinder. There are plenty of threads where folks have replaced them. Maybe one of them mentioned where it came from too?
Racer
Joined: Feb 2024
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From: New York
Thread Starter
Melting Slicks
Joined: Feb 2005
Posts: 3,472
Likes: 43
From: Auburn MA
the car seems like it stops fine and if I slam on the brakes it will activate ABS and stop fast, its just that the pedal feel is alot softer than it used to be (not nearly as firm) and i have to stroke the pedal alot more to get any response out of it. If i pump the pedal it comes up it does not get stuck to the floor
Thread Starter
Melting Slicks
Joined: Feb 2005
Posts: 3,472
Likes: 43
From: Auburn MA
I adjusted the pushrod of the booster but maybe I'll give it another look... it would make sense if that was the issue seeing as this happened right after replacing the booster.
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Melting Slicks
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Can't speak regarding the booster, but I will definitely say that a good master cylinder is hard to come by. The aftermarket ones are pretty much pot luck right out of the box for these cars. I went through three new ones until I finally found one that did the job.
It was a Raybestos Element III.
Sadly, and unfortunately, the company is victim to modern acquisition and is no more.
It was a Raybestos Element III.
Sadly, and unfortunately, the company is victim to modern acquisition and is no more.
Melting Slicks
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Haven't you been chasing brake problems for a while now? I think i remember when you adjusted the rod last year some time. Yours might be one of those instances where a complete brake job//check is in order.
Thread Starter
Melting Slicks
Joined: Feb 2005
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From: Auburn MA