Just Great - Now I have NO brakes!

[TWINRAY]

The 4 letter word many times. Problems came about when I had the great idea to put new Crypo slotted rotors and Hawk pads on. While I was at it, I put new Front wheel bearings in and resealed the calipers cause one was leaking. After all was done, after driving 5 or so miles, the brake petal lost most/all of its free play that it had when cold and at one point, there was brake drag. A few suggestions lead to the Master which I replaced with a new one. Same thing with a new hitch. After driving yesterday, I thought maybe I set the front wheel bearings one notch too tight. I reset. Went for a test ride and the petal went "real close" to the floor upon application. This AM when I went to use the car, I was surprised the BRAKE light didn't come on cause I basically had no brakes. Petal to the floor.
I have a few guesses as to WTF went wrong:
1. This new (Raybestos) Master failed completly - I guess it's possible
2. I checked runout on the front rotors after install and it was ok at .002 and .003 but I didn't check the rears. Could I be getting air pump effect and is air being pumped into the lines?
3. Is the power brake booster the problem?

Any HELP available on this? PS. New front hoses were on and I will put new rear hoses on this afternoon.

 

[wishuwerehere82]

It could be a bad MC.

But some questions first.
Did you "bench bleed" it first before installation?
Are the calipers sticking or can you push the pistons back in when the brakes lose freeplay?
Are you losing any fluid out of the MC reservoir when the lockup or loss of brakes happens?
How did the calipers cylinders look when you rebuilt them?Your calipers might be corroded to the point they are sticking or the seals leaking.
How was Watkins Glen?

First, the brake light only comes on it there is a loss of differential pressure in the lines to one or more brake calipers. If your MC is not putting out pressure, the light will not come on.

Second, the brake booster loss will not result in the loss of pedal pressure, on the contrary it will become very stiff.

Third, you can put a pressure gauge on a caliper bleeder to see if you have pressure in the system when you apply pedal pressure. This will tell you if the MC is bad or not.

Now this may sound stupid, but I have replaced a Master Cylinder before when I lost braking and afterwards found that the problem was only that my floor mats were bunched up under the brake pedal. Oh, I can laugh about it now, but then I felt so stupid.

 

[TWINRAY]

It could be a bad MC. (LOOKS LIKE IT)

But some questions first.
Did you "bench bleed" it first before installation? (YES)
Are the calipers sticking (NO) or can you push the pistons back in when the brakes lose freeplay? (YES)
Are you losing any fluid out of the MC reservoir when the lockup or loss of brakes happens? (NO)
How did the calipers cylinders look when you rebuilt them?(NO PITTING WHAT-SO-EVER) Your calipers might be corroded to the point they are sticking or the seals leaking. (THEY WERE PREVIOUSLY S/S SLEEVED)
How was Watkins Glen? (GREAT, AS ALWAYS. WILL BE THERE THIS WEEKEND AGAIN FOR THIS YEARS VINTAGE EVENT - YOU SHOULD GO!)

First, the brake light only comes on it there is a loss of differential pressure in the lines to one or more brake calipers. If your MC is not putting out pressure, the light will not come on.

Second, the brake booster loss will not result in the loss of pedal pressure, on the contrary it will become very stiff.

Third, you can put a pressure gauge on a caliper bleeder to see if you have pressure in the system when you apply pedal pressure. This will tell you if the MC is bad or not.

Now this may sound stupid, but I have replaced a Master Cylinder before when I lost braking and afterwards found that the problem was only that my floor mats were bunched up under the brake pedal. Oh, I can laugh about it now, but then I felt so stupid.

Questions answered about in brackets.
Looks like the new MC was bad. I installed new rear hoses. I did the fronts last week. After installing the real hoses (after the total brake failure) I could not bleed the calipers with the NEW Raybestos MC. Nothing would come out of the rear calipers using the Motive bleeder. Decided the new unit went South. Took the old MC out of the box that the new one came in. Bench bleed it. Went according to instructions. Installed old MC and bleed all calipers including the MC. I now have a very good petal upon start up. Previously with this old MC and the new MC before it crapped out, the petal would be kinda low upon startup. Drove to work this AM, 8 miles, and petal did seem to loose free play like before but it still was OK. I now think the high petal could be due to the new "full sized" rotors and new pads. I think I will loosen the power booster push rod maybe a triffle, say 1/32" so it gives me a bit more free play when hot. A lot has to be said about the motto, If it's not broken, don't fix it.

 

[TWINRAY]

I'm putting this thread to bed with what happened after a 700 mile round trip to Watkins Glen this past weekend. I've returned the new Raybestos MC to the dealer and we have deemed it a failure. I did not have any low brake petal issues during the trip. I There are times, usually just after driving a few miles, when stopped and in DRIVE with my foot off the brake that the car does not move. Most of the time it is OK and the car will creep forward. I am guessing that pistons in one of the calipers are sticking. It is hard to determine what wheel it is because you would have to jack the car up when the problem occurs and that is not entirely possible when you are on the road. I hope to isolate what wheel is sticking and check that particular caliper out. I may also now, since only local trips are in the making, just drive it and see if say just a seal is sticking, maybe it will "work its way out." Either way, the small block got close to 20 mpg at speeds up to 75 cruising.

PS. I never changed the length of the booster push rod.

 

[67HEAVEN]

Thanks for the update.

 

[gmjunkie]

I'm putting this thread to bed with what happened after a 700 mile round trip to Watkins Glen this past weekend. I've returned the new Raybestos MC to the dealer and we have deemed it a failure. I did not have any low brake petal issues during the trip. I There are times, usually just after driving a few miles, when stopped and in DRIVE with my foot off the brake that the car does not move. Most of the time it is OK and the car will creep forward. I am guessing that pistons in one of the calipers are sticking. It is hard to determine what wheel it is because you would have to jack the car up when the problem occurs and that is not entirely possible when you are on the road. I hope to isolate what wheel is sticking and check that particular caliper out. I may also now, since only local trips are in the making, just drive it and see if say just a seal is sticking, maybe it will "work its way out." Either way, the small block got close to 20 mpg at speeds up to 75 cruising.

PS. I never changed the length of the booster push rod.

I'd Check Caliper that was Leaking First Probly a little Bitty teensy weentsy rust pit!! junk!!