brake problem - Page 2

gmonde · 12-24-2007, 07:55 PM

sounds like a master cylinder problem,try this ,plug all four lines at the calipers(you can do this with plugs for #4 line ,this dead heads the master,(i asume that you have braided lines)if the master is bad you wont be able to get a pedal no matter how much you bleed at the lines,if the pedal is hard,hook up one line at a time to the calipers could be a caliper piston lip seal not holding the piston out to the pad

gmonde

Mike Hedger · 12-25-2007, 10:47 AM

First off the corvette master cyl. was designed for a car with 4 piston 4 wheel disk brakes so it moves enough fluid for the willwood callipers but it is not a quick take up like the Chrysler unit so it needs all of its stroke to move the amount of fluid you will need to stop the car. Second you said the pushrod is not hitting the MC piston untill it is about 3" from the floor? If this correct that is your problem, make or buy a longer pushrod. I like to give the MC about 1/4" of freeplay so you don't cover up the compensating or return ports otherwise you will have pressure on the system at all times. Hope this helps and have a merry Christmas, Mike

Dave Goob Cook · 12-26-2007, 04:16 AM

Gotta have full stroke.
Full bottom and full return first and foremost, with positive retention of the pushrod in the M/C please!!!!!

No need for the valving, but it won't kill ya either.....

Any factory valves have been removed, correct?

M/C is higher than the calipers?
Lines need to not run "up" at any point out of the M/C. (Line-Lock or pressure gauge plumbing?)

Bench bleed, install M/C keeping the outlets turned "up" as much as possible, while you finger in the lines, mount it, leave the lines cracked just a touch while an assistant strokes the pedal all the way down and holds it, while you snug the lines. Then gravity bleed it at all 4, shut off as fluid flows to each one, then start a "normal" bleed process.

Sometimes if the lines have been flushed or dry, you should open all bleeders, stroke the pedal full down and hold, close bleeders, let pedal up, repeat as needed, to get as much air out initially as possible.

I've had to do brakes alone for years, found some tricks. I've replaced many M/C's without the need for any bleeding, only flushing out of the old fluid....
Speaking of that, the lines were clear and dry, no kinks or dents, no excess moisture around when the system was open?
Any possibility of fluid contamination?

Remember that some braided steel lines (non hard Teflon liner) will give you a spongy pedal, and the brake pedal never feels "hard" enough until the new pads/shoes are bedded in properly.

IF you are using a Silicone fluid, there are more details to follow.
Been there, done that, nothing wrong with it at all, you just have to treat it differently.

I like Valvoline Synpower brake fluid.

denny harvey · 12-26-2007, 03:41 PM

OK,the MC looks like its getting full travel at the push rod,i checked the depth on the bench and in the car.the pedal at rest is 41/2 to 5 inches off the floor.so now i will plug up MC and see if it holds..i hope its a bad MC..any of you camaro guys had to change the push rod when switching to disc ???

Joe Martens · 12-26-2007, 10:06 PM

Denny, I replaced the stock master cylinder with a Strange master cylinder and I have 4 wheel disc brakes. It has the 1.125 bore, part # is B3359BK, which comes with adapter fittings and a pushrod with a rubber sleeve at the tip so it keeps it inside of the piston. I do not run a proportioning valve. I have not had any problems.

denny harvey · 12-29-2007, 05:26 PM

OK,the MC holds a strong pedal when i dead headed it ,i called wilwood about the pushrod and they told me how to measure it ,it also is ok.?? so i guess the system is full of air..now to get it out.thanks for the help guys...and i thought my soft-loc clutch set-up was tough........

Chris DeGidio · 12-29-2007, 05:41 PM

I used a bleeding system called Vacula.It works great.

www.vacula.com

Kevin Lang · 12-29-2007, 09:39 PM

Denny, check the adustable prop valve to make sure it is not closed up, by turning the knob somewhere close to center on the adjustment. Otherwise you will have less pressure and slow bleeding at rear brakes thus taking forever to get the air out. good luck!!!

Chris DeGidio · 12-29-2007, 10:39 PM

Quote:

Originally Posted by 1664SSJA

Chris,

Which one of the four do you have? The vacuum bleeder? What is the cost?

Mark

I have what they now call the Drainman auto kit. I bought mine a few years ago,I think I paid around $55.00.I have seen them on Ebay.

I also use the Valvoline SynPower brake fluid.It's not a silicone fluid,but it has a higher temp than the DOT 3 or 4 fluid.

12-24-2007, 07:55 PM	#11
gmonde Senior Member Join Date: Nov 2007 Posts: 615 Likes: 56 Liked 166 Times in 59 Posts	Re: brake problem sounds like a master cylinder problem,try this ,plug all four lines at the calipers(you can do this with plugs for #4 line ,this dead heads the master,(i asume that you have braided lines)if the master is bad you wont be able to get a pedal no matter how much you bleed at the lines,if the pedal is hard,hook up one line at a time to the calipers could be a caliper piston lip seal not holding the piston out to the pad gmonde

12-25-2007, 10:47 AM	#12
Mike Hedger Junior Member Join Date: Jul 2007 Location: Kemah TX Posts: 93 Likes: 0 Liked 1 Time in 1 Post	Re: brake problem First off the corvette master cyl. was designed for a car with 4 piston 4 wheel disk brakes so it moves enough fluid for the willwood callipers but it is not a quick take up like the Chrysler unit so it needs all of its stroke to move the amount of fluid you will need to stop the car. Second you said the pushrod is not hitting the MC piston untill it is about 3" from the floor? If this correct that is your problem, make or buy a longer pushrod. I like to give the MC about 1/4" of freeplay so you don't cover up the compensating or return ports otherwise you will have pressure on the system at all times. Hope this helps and have a merry Christmas, Mike __________________ Mike Hedger S/C 4646 MPH Racing and Fabrication

12-26-2007, 04:16 AM	#13
Dave Goob Cook Member Join Date: Dec 2006 Location: Indy Posts: 422 Likes: 0 Liked 0 Times in 0 Posts	Re: brake problem Gotta have full stroke. Full bottom and full return first and foremost, with positive retention of the pushrod in the M/C please!!!!! No need for the valving, but it won't kill ya either..... Any factory valves have been removed, correct? M/C is higher than the calipers? Lines need to not run "up" at any point out of the M/C. (Line-Lock or pressure gauge plumbing?) Bench bleed, install M/C keeping the outlets turned "up" as much as possible, while you finger in the lines, mount it, leave the lines cracked just a touch while an assistant strokes the pedal all the way down and holds it, while you snug the lines. Then gravity bleed it at all 4, shut off as fluid flows to each one, then start a "normal" bleed process. Sometimes if the lines have been flushed or dry, you should open all bleeders, stroke the pedal full down and hold, close bleeders, let pedal up, repeat as needed, to get as much air out initially as possible. I've had to do brakes alone for years, found some tricks. I've replaced many M/C's without the need for any bleeding, only flushing out of the old fluid.... Speaking of that, the lines were clear and dry, no kinks or dents, no excess moisture around when the system was open? Any possibility of fluid contamination? Remember that some braided steel lines (non hard Teflon liner) will give you a spongy pedal, and the brake pedal never feels "hard" enough until the new pads/shoes are bedded in properly. IF you are using a Silicone fluid, there are more details to follow. Been there, done that, nothing wrong with it at all, you just have to treat it differently. I like Valvoline Synpower brake fluid. Last edited by Dave Goob Cook; 12-26-2007 at 04:21 AM.

12-26-2007, 03:41 PM	#14
denny harvey Member Join Date: Nov 2003 Location: pataskala ohio Posts: 132 Likes: 0 Liked 0 Times in 0 Posts	Re: brake problem OK,the MC looks like its getting full travel at the push rod,i checked the depth on the bench and in the car.the pedal at rest is 41/2 to 5 inches off the floor.so now i will plug up MC and see if it holds..i hope its a bad MC..any of you camaro guys had to change the push rod when switching to disc ???

12-26-2007, 10:06 PM	#15
Joe Martens Senior Member Join Date: Dec 2001 Location: North Olmsted, Ohio Posts: 772 Likes: 551 Liked 181 Times in 62 Posts	Re: brake problem Denny, I replaced the stock master cylinder with a Strange master cylinder and I have 4 wheel disc brakes. It has the 1.125 bore, part # is B3359BK, which comes with adapter fittings and a pushrod with a rubber sleeve at the tip so it keeps it inside of the piston. I do not run a proportioning valve. I have not had any problems. __________________ Joe Martens A/Stock 3969

12-29-2007, 05:26 PM	#16
denny harvey Member Join Date: Nov 2003 Location: pataskala ohio Posts: 132 Likes: 0 Liked 0 Times in 0 Posts	Re: brake problem OK,the MC holds a strong pedal when i dead headed it ,i called wilwood about the pushrod and they told me how to measure it ,it also is ok.?? so i guess the system is full of air..now to get it out.thanks for the help guys...and i thought my soft-loc clutch set-up was tough........

12-29-2007, 05:41 PM	#17
Chris DeGidio Member Join Date: Jun 2007 Posts: 364 Likes: 8 Liked 2 Times in 2 Posts	Re: brake problem I used a bleeding system called Vacula.It works great. www.vacula.com __________________ Nautilus Racing

12-29-2007, 09:39 PM	#18
Kevin Lang Junior Member Join Date: Apr 2003 Location: southern connecticut Posts: 38 Likes: 5 Liked 0 Times in 0 Posts	Re: brake problem Denny, check the adustable prop valve to make sure it is not closed up, by turning the knob somewhere close to center on the adjustment. Otherwise you will have less pressure and slow bleeding at rear brakes thus taking forever to get the air out. good luck!!!