Work up from winter slumber with a problem
Thread Starter
Instructor
Joined: Oct 2014
Posts: 151
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From: Capital District, NY
Work up from winter slumber with a problem
The weather has been pretty nice here in NY over the last few days, so I decided to get my 87 out of winter storage. Happily, it started right up without a hiccup... but the brake pedal went right to the floor.
Master cylinder reservoir was empty. *sigh*.
I checked the master cylinder and all 4 wheels and there's no signs of leakage.
To be honest, I can't remember the last time I checked it, so it may have been low for a long time. Top it off, and now when I pump the brake with the car off, the pedal gets hard, then slowly goes down. Fluid in the reservoir is dark.
If I pump the pedal with the car running (or when I start the car with my foot on the pedal) as soon as it turns on, the pedal goes right to the floor.
Thoughts on where to start? Where could that fluid have gone?
Master cylinder reservoir was empty. *sigh*.
I checked the master cylinder and all 4 wheels and there's no signs of leakage.
To be honest, I can't remember the last time I checked it, so it may have been low for a long time. Top it off, and now when I pump the brake with the car off, the pedal gets hard, then slowly goes down. Fluid in the reservoir is dark.
If I pump the pedal with the car running (or when I start the car with my foot on the pedal) as soon as it turns on, the pedal goes right to the floor.
Thoughts on where to start? Where could that fluid have gone?
Thread Starter
Instructor
Joined: Oct 2014
Posts: 151
Likes: 1
From: Capital District, NY
Edit: Clean as a whistle in there, no leaks.
Master cylinder builds up pressure, and the brake booster let's out a hiss when I remove the vacuum hose, so there's pressure there too. My gut says both are fine.
Last edited by drsfmd; Mar 12, 2016 at 11:22 AM.
Thread Starter
Instructor
Joined: Oct 2014
Posts: 151
Likes: 1
From: Capital District, NY
How would I go about diagnosing this? Why would it build pressure when the car is off, and lose it immediately when the car is started?
Thread Starter
Instructor
Joined: Oct 2014
Posts: 151
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From: Capital District, NY
http://vetteco.com/catalog/index.php...age=page&id=17
This link would seem to imply that the pedal would get HARD not soft if the booster were shot.
This link would seem to imply that the pedal would get HARD not soft if the booster were shot.
Race Director
Joined: Mar 2015
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http://vetteco.com/catalog/index.php...age=page&id=17
This link would seem to imply that the pedal would get HARD not soft if the booster were shot.
This link would seem to imply that the pedal would get HARD not soft if the booster were shot.
Last edited by antfarmer2; Mar 12, 2016 at 11:43 AM.
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Thread Starter
Instructor
Joined: Oct 2014
Posts: 151
Likes: 1
From: Capital District, NY
*sigh* you suggested it in your first post.
So, if you're right that the the master cylinder is leaking into the brake booster, what do I need to do to confirm that? There isn't a spec of fluid on the outside of the booster or the master cylinder.
So, if you're right that the the master cylinder is leaking into the brake booster, what do I need to do to confirm that? There isn't a spec of fluid on the outside of the booster or the master cylinder.
Race Director
Joined: Mar 2015
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Did you find fluid in the abs storage? Are you loosening fluid? Have you found any leaks now that you put fluid in?
I cannot see it from here.
Feel up by your pedal and your carpet too.
I cannot see it from here.
Feel up by your pedal and your carpet too.
Last edited by antfarmer2; Mar 12, 2016 at 11:59 AM.
Thread Starter
Instructor
Joined: Oct 2014
Posts: 151
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From: Capital District, NY
After my last post I took it for a ride around the block, in the hopes that something was seized up and might unsieze.
Half an hour later, there are a few drips on the driveway, and it appears to be coming from the joint where the booster and the master cylinder come together. So it looks like I need a master cylinder.
How (or do I need to) get whatever fluid I assume has leaked into the booster out? Could the booster have been damaged?
Half an hour later, there are a few drips on the driveway, and it appears to be coming from the joint where the booster and the master cylinder come together. So it looks like I need a master cylinder.
How (or do I need to) get whatever fluid I assume has leaked into the booster out? Could the booster have been damaged?
Safety Car
Joined: Sep 2010
Posts: 3,752
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From: Indiana PA
After my last post I took it for a ride around the block, in the hopes that something was seized up and might unsieze.
Half an hour later, there are a few drips on the driveway, and it appears to be coming from the joint where the booster and the master cylinder come together. So it looks like I need a master cylinder.
How (or do I need to) get whatever fluid I assume has leaked into the booster out? Could the booster have been damaged?
Half an hour later, there are a few drips on the driveway, and it appears to be coming from the joint where the booster and the master cylinder come together. So it looks like I need a master cylinder.
How (or do I need to) get whatever fluid I assume has leaked into the booster out? Could the booster have been damaged?
Brakes are not something to mess around with IMHO. Given the age of the booster and LIKELY contamination, replacement is the prudent thing to do.
Thread Starter
Instructor
Joined: Oct 2014
Posts: 151
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From: Capital District, NY
Ok... I am prepared to order a new MC and booster.
Anyone have an opinion on the RAYBESTOS MC39621 master cylinder? I can get it for $112 at Rock auto.
Similarly, an OEM booster remanufactured by Durastop is $96-- a non-reman is $325, so unless there's a really compelling reason to spend an extra $229 on the part, I don't intend to do so.
Thoughts on either part would be welcome.
Anyone have an opinion on the RAYBESTOS MC39621 master cylinder? I can get it for $112 at Rock auto.
Similarly, an OEM booster remanufactured by Durastop is $96-- a non-reman is $325, so unless there's a really compelling reason to spend an extra $229 on the part, I don't intend to do so.
Thoughts on either part would be welcome.
