Brake weirdness
Thread Starter
Burning Brakes
Joined: May 2017
Posts: 774
Likes: 375
From: Seattle WA
Brake weirdness
Hi All,
I am having something strange happening to my 68 brakes.
I have Wilwood brakes all around with a Wilwood master cylinder. MANUAL brakes. No booster.
I bled them months ago and have had a firm pedal. When I push hard on the pedal, it does not slowly sink at all. However, starting a month ago, every once in a while when I go to push the brakes, the pedal goes down about half way before it starts braking. If I let the pedal up and push again it is back to normal. It seems weird that it is very inconsistent as to when it happens, so it doesn't seem like there is air in there. Wouldn't that do it every time?
Figured I would check with you all before taking to the time to bleed the brakes again.
Any thoughts?
I am having something strange happening to my 68 brakes.
I have Wilwood brakes all around with a Wilwood master cylinder. MANUAL brakes. No booster.
I bled them months ago and have had a firm pedal. When I push hard on the pedal, it does not slowly sink at all. However, starting a month ago, every once in a while when I go to push the brakes, the pedal goes down about half way before it starts braking. If I let the pedal up and push again it is back to normal. It seems weird that it is very inconsistent as to when it happens, so it doesn't seem like there is air in there. Wouldn't that do it every time?
Figured I would check with you all before taking to the time to bleed the brakes again.
Any thoughts?
Race Director
Joined: May 2003
Posts: 10,956
Likes: 409
From: California
Hi All,
I am having something strange happening to my 68 brakes.
I have Wilwood brakes all around with a Wilwood master cylinder. MANUAL brakes. No booster.
I bled them months ago and have had a firm pedal. When I push hard on the pedal, it does not slowly sink at all. However, starting a month ago, every once in a while when I go to push the brakes, the pedal goes down about half way before it starts braking. If I let the pedal up and push again it is back to normal. It seems weird that it is very inconsistent as to when it happens, so it doesn't seem like there is air in there. Wouldn't that do it every time?
Figured I would check with you all before taking to the time to bleed the brakes again.
Any thoughts?
I am having something strange happening to my 68 brakes.
I have Wilwood brakes all around with a Wilwood master cylinder. MANUAL brakes. No booster.
I bled them months ago and have had a firm pedal. When I push hard on the pedal, it does not slowly sink at all. However, starting a month ago, every once in a while when I go to push the brakes, the pedal goes down about half way before it starts braking. If I let the pedal up and push again it is back to normal. It seems weird that it is very inconsistent as to when it happens, so it doesn't seem like there is air in there. Wouldn't that do it every time?
Figured I would check with you all before taking to the time to bleed the brakes again.
Any thoughts?
Please post a picture of the brake fluid in the bowl
If the fluid is black or dark/greenish, this comes from water entering the system and then super boiling, when this is done it creates air in the system, giving the symptoms you are describing.
Last edited by pauldana; Jul 5, 2019 at 01:42 PM.
Thread Starter
Burning Brakes
Joined: May 2017
Posts: 774
Likes: 375
From: Seattle WA
Melting Slicks
Joined: Jun 2011
Posts: 3,116
Likes: 598
Hi All,
I am having something strange happening to my 68 brakes.
I have Wilwood brakes all around with a Wilwood master cylinder. MANUAL brakes. No booster.
I bled them months ago and have had a firm pedal. When I push hard on the pedal, it does not slowly sink at all. However, starting a month ago, every once in a while when I go to push the brakes, the pedal goes down about half way before it starts braking. If I let the pedal up and push again it is back to normal. It seems weird that it is very inconsistent as to when it happens, so it doesn't seem like there is air in there. Wouldn't that do it every time?
Figured I would check with you all before taking to the time to bleed the brakes again.
Any thoughts?
I am having something strange happening to my 68 brakes.
I have Wilwood brakes all around with a Wilwood master cylinder. MANUAL brakes. No booster.
I bled them months ago and have had a firm pedal. When I push hard on the pedal, it does not slowly sink at all. However, starting a month ago, every once in a while when I go to push the brakes, the pedal goes down about half way before it starts braking. If I let the pedal up and push again it is back to normal. It seems weird that it is very inconsistent as to when it happens, so it doesn't seem like there is air in there. Wouldn't that do it every time?
Figured I would check with you all before taking to the time to bleed the brakes again.
Any thoughts?
https://www.corvetteforum.com/forums...-cylinder.html
What brand of brake fluid are you using ?
Pro
Joined: Mar 2014
Posts: 529
Likes: 113
From: Texas
Start by cleaning all the dirt out of the master cylinder, then flush out the entire brake system. Use DOT 5 fluid (Wilwood recommended). You may just be pulling dirt through the master cylinder causing a bypass of fluid.
Thread Starter
Burning Brakes
Joined: May 2017
Posts: 774
Likes: 375
From: Seattle WA
I have DOT3 in it right now so I just ordered a boatload of DOT5 and I will flush it.
between now and then I will back up my driveway which is steep enough to get the back of the MC higher than the front to bleed it more.
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Pro
Joined: Jun 2014
Posts: 706
Likes: 294
From: New Jersey
It is only 6 months old. Brand new from Wilwood.
I have DOT3 in it right now so I just ordered a boatload of DOT5 and I will flush it.
between now and then I will back up my driveway which is steep enough to get the back of the MC higher than the front to bleed it more.
I have DOT3 in it right now so I just ordered a boatload of DOT5 and I will flush it.
between now and then I will back up my driveway which is steep enough to get the back of the MC higher than the front to bleed it more.
With light pressure on the brake pedal, can you get the pedal to sink to the floor?
Does wilwood have a warranty on the master?
What do they think about the issues you are having?
Thread Starter
Burning Brakes
Joined: May 2017
Posts: 774
Likes: 375
From: Seattle WA
Wilwood seems Ed’s to be closed today so I haven’t had a chance to talk to them.
Thread Starter
Burning Brakes
Joined: May 2017
Posts: 774
Likes: 375
From: Seattle WA
i backed it up and pumped it more. About five bubbles so small I almost couldn’t see them came out. That’s good. But then I took it for a test drive and it still does it once in a while.
I will I’ll call Wilwood and see what they say Monday.
Pro
Joined: Jun 2014
Posts: 706
Likes: 294
From: New Jersey
I take it back. When it is acting up it does slowly go to the floor.
i backed it up and pumped it more. About five bubbles so small I almost couldn’t see them came out. That’s good. But then I took it for a test drive and it still does it once in a while.
I will I’ll call Wilwood and see what they say Monday.
i backed it up and pumped it more. About five bubbles so small I almost couldn’t see them came out. That’s good. But then I took it for a test drive and it still does it once in a while.
I will I’ll call Wilwood and see what they say Monday.
Make sure you tell them that.
I have run into a similar issue with M/C clutch masters that we fixed with Ate brake fluid.
Ate fluid tends to swell the seals a little.
however
brake are too important to use that as a cure.
Thread Starter
Burning Brakes
Joined: May 2017
Posts: 774
Likes: 375
From: Seattle WA
It will be several weeks before I get around to that (Vegas this weekend and Savannah, GA next weekend) but I will try that. I will figure out how to build a fitting for that between now and then so I can use my power bleeder.
BTW he said that DOT3 fluid is fine. They only recommend DOT5 for show cars. So I am going to send back the $123 of DOT5 I bought!
Pro
Joined: Jun 2014
Posts: 706
Likes: 294
From: New Jersey
A few issues with Silicon are that:
It is hard to bleed, air forms micro bubbles in it, that are difficult to get rid of.
If any water gets in the system it pools at the lowest parts. Since it is not miscible in water, it tens to stay there and cause rust.
Any residual water in the caliper will boil at a lower temp than brake fluid does.
It does not lubricate EPDM seals as well as brake fluid does.
It is hard to bleed, air forms micro bubbles in it, that are difficult to get rid of.
If any water gets in the system it pools at the lowest parts. Since it is not miscible in water, it tens to stay there and cause rust.
Any residual water in the caliper will boil at a lower temp than brake fluid does.
It does not lubricate EPDM seals as well as brake fluid does.
Pro
Joined: Mar 2014
Posts: 529
Likes: 113
From: Texas
This is the brake fluid I use in my cars and customer cars. Most parts stores sell it.
https://www.oreillyauto.com/detail/b...6231635?pos=16
https://www.oreillyauto.com/detail/b...6231635?pos=16
Thread Starter
Burning Brakes
Joined: May 2017
Posts: 774
Likes: 375
From: Seattle WA
This is the brake fluid I use in my cars and customer cars. Most parts stores sell it.
https://www.oreillyauto.com/detail/b...6231635?pos=16
https://www.oreillyauto.com/detail/b...6231635?pos=16
Pro
Joined: Mar 2014
Posts: 529
Likes: 113
From: Texas
