Community Forums

Bcollier9253 · 08-03-2013, 09:53 AM

I'm trying to gravity bleed my brakes but can't get any fluid to come out of the front. Just out if curiosity I loosened the master cylinder from the hydroboost unit and it allowed fluid to flow. So is the pushrod to long or is the brake pedal linkage out of adjustment. It is a brand new hydro that instructed me to use the old pushrod.

Skip426 · 08-03-2013, 10:43 AM

Quote:

Originally Posted by Bcollier9253

I'm trying to gravity bleed my brakes but can't get any fluid to come out of the front. Just out if curiosity I loosened the master cylinder from the hydroboost unit and it allowed fluid to flow. So is the pushrod to long or is the brake pedal linkage out of adjustment. It is a brand new hydro that instructed me to use the old pushrod.

Was the pushrod adjustable ? Sound like it is a little to long.
Can you contact the hydro boost unit supplier for guidance ?

Bcollier9253 · 08-03-2013, 10:49 AM

I just called Nappa, he didn't have any info so he said he would call the manufacturer Monday which really doesn't do a thing for me now

Skip426 · 08-03-2013, 10:53 AM

If your in a hurry , you could try , adjusting the pedal linkage ; BUT mark every thing so you can return it to the original position if necessary.

Bcollier9253 · 08-03-2013, 11:03 AM

Thanks, I may just try that. It's not that I'm in a hurry... Well maybe a little, I have been jacking with these brakes off and on after work and on the weekends for three weeks now!! I'm done with it, ready to be camping!! Lol!! My boat is in the garage waiting for the exhaust tube and engine to be put back in. Project # 2 of many. Yup, out last outing the boat sank, coach brakes locked up on the way home had to be towed and after we had been home for a week the tranny went out of my 01 F350!!

Skip426 · 08-03-2013, 11:22 AM

Oh , boy, and I thought I was having fun.
Spent 3 1/2 hours accessing a 22c O ring on my HEUI pump to stop a persistent oil leak. Had to modify 3 wrenches to complete the job. I now have the wrenches and extra O rings in my tool box , theory being, if you have spares you will never need them .

Bcollier9253 · 08-03-2013, 11:28 AM

True true. Good luck !

Old Trucker · 08-03-2013, 12:49 PM

Quote:

Originally Posted by Skip426

Was the pushrod adjustable ? Sound like it is a little to long.
Can you contact the hydro boost unit supplier for guidance ?

Howdy, I have not replaced the hydro booster on mine. But you say your brakes locked up. Are you sure that the master cylinder was not the culprit???? I lost my brakes 3 times. Replaced everything BUT the hydro boost. Be absolutely certain you have a good flush on your fluid. It appears that your coach may have a little age. old fluid can be extremely expensive in the end. I do not know if a gravity flow is sufficient. I would want to be absolutely sure if I had done that much brake work. It would be a shame to have to repeat it again. I would be talking to someone smarter than I. My brake job ended up 2 tickets totaling over $3700. good wishes, old trucker

sc3283 · 08-04-2013, 12:56 AM

Bcoll, make sure your brake pedal is returning fully...many times pedal linkages get rusty,dusty,dirty and bind....not allowing pedal to return fully

stink · 08-04-2013, 01:02 AM

I would reinstall master to hydroboost and then remove linkage from brake pedal and see if you have fluid flow. This will isolate problem as pedal may be bound up or a brake light/cruise switch may be hanging up. The pushrod from hydroboost and master I don't think is adjustable but the rod from brake pedal to hydroboost is.

Bcollier9253 · 08-04-2013, 05:22 AM

The old master when put against the hydro would start to make contact with the pushrod before the two were seated together. Bench bled the new master again and put it up there, it was fine. We bled for quite a bit and got a lot better pedal but did notice that the pedal has some slip in it before it pushes the input rod into the hydro, that is today's project. I think she is getting real close !! Thanks everyone for their suggestions!

Bcollier9253 · 08-04-2013, 05:41 AM

I meant to say the pedal has some slop in it not slip.

Bcollier9253 · 08-04-2013, 05:48 AM

I was on the phone yesterday for about an hour with Dave78 Chief, we both had a hunch that the master was being partially held open and not allowing any fluid to get to the piston. That assumption was spot on. This guy sounds to be pretty knowledgeable in brake systems, I would suggest if anyone has problems give him a look.

gemini5362 · 08-04-2013, 01:31 PM

I have gravity bled brakes on cars before and one of the things i forget every once in a while is to leave the master cylinder cap off while it is draining
. With the cap in place it does not seem to drain very well.