littlevette

Hey, Guys - Please Help!!

My husband and son are having problems with the brakes on my 1955 Corvette. He and my son are doing a complete brake job on the car. They rebuilt the cylinders with silicone brake fluid. Cylinders are leaking fluid. They have now rebuilt the cylinders several times with the silicone brake fluid. Could it be the silicone brake fluid causing the cylinders to leak? They have been told to add a metal expander behind the rubber cup seal. However, they can't find the metal expanders. If a metal expander is needed, where can they be purchased?
What are your thoughts on all of this? Right now, I have a very frustrated husband and son!!! Please Help!!!!

littlevette

Geralds57

That's odd that all of them leak. Why did they rebuild all of them? Has the car been sitting for years? I dont think the silicone has any bearing on them leaking. If they're pitted really bad on the inside, they will need to be sleeved. Since they've had then apart several times, I would just buy new replacements and be done.

jim lockwood

The silicone fluid, as Gerald indicated, has no bearing on the leaking. I, too, think the smart move would be to go to NAPA and buy a brand new set of wheel cylinders. They are inexpensive and guaranteed.

Jim

littlevette

Hi, Jim and Gerald
Thanks so much for your response. This is a NCRS Top Flight car, so we want to keep it as original as possible. All wheel cylinders have been sleeved with stainless steel inserts. The cylinders don't leak, until the car sits for 3-6 months. This is so frustrating to both my husband and son. Any ideas on keeping the silicone from leaking? Should the silicone be removed and replaced with regular brake fluid? I know that both of you said that you don't think it is the silicone brake fluid, but I think that they are out of ideas. This car is very important to me, as it was in my "bucket list" for a very long time. I would greatly appreciate any ideas, etc. on what to do with the brakes. It is a beautiful car and I love it. However, it would be nice to drive it safely,
Thanks,
littlevette

jim lockwood

LV,

First off, you can absolutely, positively, without any doubt ignore silicone fluid as a cause of leaks. This is a non-issue. I and a gazzillion others successfully have used it for decades. In fact, my own '54 Corvette has it in its brake system.

I think the residual pressure valve in the master cylinder has failed. Its purpose is to keep about 10 PSI in the brake lines at all times. This slight pressure keeps the wheel cylinder seals pushed out against the wheel cylinder sleeves.

Looking at the NAPA web page, I don't see where they are available individually. To replace the one in your '55's master cylinder you'll need to purchase a rebuild kit.

Ask for NAPA part number UP3.

And just for reference, the residual pressure valve is the little gadget in the lower left corner of this picture:



Jim

1955 copper

I may be just me but for 54 years normal brake fluid has and still works OK on my original cylinders that were sleeved years ago.
Metal expander??? Don't know what their talking about. Cost is not much I would go back to normal fluid buy new kits being sure you have the correct kits. I love 55's how about a pic?

littlevette

Hi, Guys,
Thanks so much for the info. I will give this info to my husband and son. It is great to be able to post a question and have info by "people who have been there".
I will have to post a picture. My 55' Vette is Gypsy Red and it is the original color. I have pictures of the car as it was being resored and you can see where the original color was. A 55' Vette was on my Bucket list and now I have one.
Thanks to all of you. I appreciate the info. Hopefully, in the near future, I will not have to listen to my husband and son and their frustration with the brakes.
Thank You All,
littlevette

rene-paul

Could the brake wheel cylinder "cups" be reversed?
Brgds,
Rene

jim lockwood

Many decades and lifetimes ago, when I lived in NW Georgia, I had a Gypsy Red '55, #1236. That's not your car, is it?

Jim

littlevette

Hi, Jim,
No, this was not your gypsy red corvette. This one is in the late 600s' production. The owner that we purchased it from was from Indiana. I have a 1954 Corvette, also. As you can tell, I love the "Little Corvettes", so my log in name is "littlevette". Thanks so much for all the help.
littlevette aka Carolyn

littlevette

Hello, Rene

I am going to ask my husband this question. I sincerely "Thank You" for your response. My husband and son are so frustrated and tired of dealing with the brakes on the car. I hope that they figure it out.

Thanks again,
littlevette aka, Carolyn

Boyan

Dont let it sit for months at a time. It needs to be driven.

jim lockwood

Indiana? Well even tho that's not my old car, that's just eerie. I had heard a rumor that my old car had gone to Indiana some time after I sold it in '72.

Do post some pictures of your '54 and '55 when you get a chance, OK?

And do check on the residual pressure valve in the master cylinder. I bet that's the problem.

Jim

littlevette

Hello, Boyan
I know you are so right about driving the car. I purchased the car a little over a year ago and it had sat for a long time. It had been a display car and not driven. It will now be enjoyed. I , certainly won't be driving it to the grocery store, but it will be driven and loved. Thanks so much for your reply.
littlevette

DZAUTO

That was EXACTLY my thought--------------------especially if all 4 are leaking!

csherman

Question
who did the SS insert? and is it the right I.D.?
If all are leaking - something is wrong
and second like above are the cup reversed - easy to do.
the fluid is not the issue - but it is slippery than .....

MikeM

Just my opinion because I've never put the cups in backwards, I don't think you'd have any brakes at all. The fluid would just blow by the inverted lip seals.

Decades ago, (1930's) much of the rubber used in brake systems was not compatible with silicone fluid. Sometime in the last 60-70 years, that problem has been rectified due to change in the materials. There should be nothing left on the shelf today that wouldn't like the silicone. I would use the silicone fluid and remove it from the suspect list.

As mentioned above since all four are leaking, it might be the diameter of the of the sleeved wheel cylinders causing the problem. That's easy enough to measure. Also inspect the bores for irregular diameter, roughness, etc. If someone mentioned "expanders" that might mean that person knows more than what's been told here.

On the other had, do we really know the fluid is blowing by the cup seals or is it leaking out of the fittings?

Short of finding a solution, I would purchase new cylinders as mentioned above.