Brakes

NEVRL8T · 01-23-2011, 5:28pm

My car (1992 auto, 160K miles), at start up, and for a while after that, has a brake pedal problem. It's not the pedal really and I think I know what the diagnosis is probably going to be, but I wanted some opinions. The pedal will go nearly to the floor and I suspect the brake booster is going out. You can pump it up but it will lose pressure quickly. Once it's good and warmed up it will hold pressure pretty well. I had Hawk HPS pads installed in June of 2008 and have maybe 2000 miles on them. There is plenty of brake fluid in the resevoir and the problem started about six months ago. I do not know how to do a brake job so your dealing with a novice here. I have done things like replaced the injectors and I always change my own oil and air filter. I want to tackle bigger projects like changing my heater core, which it needs, and I have an MSD opti and wires ready for when they go. My car has the original opti on it now. So please cut me some slack.

NEVRL8T · 01-23-2011, 5:48pm

Shit, wrong forum. Yo, RedLS1 - can you move this to C4 Tech?

Frizlefrak · 01-23-2011, 5:59pm

It sounds like you have air in the lines. Air compresses, liquid doesn't...thus the soft pedal. I would start by fully bleeding the system and in doing so, changing your brake fluid.

Has the master cylinder been off the car? If so, it will need to bled separately.

If not, pick up a couple of big cans of brake fluid, a container to catch it in, a six pack of beer, a helper, and a mighty vac to siphon out the master cylinder.

Siphon out the master cylinder first, and wipe it clean once it's empty. Refill with fresh fluid. Now....there are a number of ways you can do this....speed bleeders, mighty vac, etc....but I prefer to just open the bleeders and have a helper press the pedal while I watch. Start with the wheel that is furthest from the master cylinder (right rear). Open the bleeder, and have your buddy press the pedal to the floor and hold it. Tighten the bleeder, and then have him release the pedal. You will most likely see dirty fluid and air bubbles.....bubbles are bad. Continue doing this until you have clear fluid and NO bubbles. You should be able to finish beer #1.

Once it runs clear and has no more air bubbles, cap it up and move to the next closest wheel (left rear). Repeat on this wheel, opening and consuming beer #2. Once it runs clear and has no air, cap it up. Don't forget to keep checking that master cylinder. It may take several cycles at each wheel to clear the bubbles and old fluid.

Next wheel, right front, and beer #3. After you check the master cylinder and refill, hit the bathroom....you're getting close to being done.

Finish off with the left front, refill the master, and cap it off.

You should now have a firm pedal. If not, something is wrong in the system and needs to be addressed ASAP.

RedLS1GTO · 01-23-2011, 6:03pm

Quote:

Originally Posted by NEVRL8T

can you move this to C4 Tech?

Done...

...and as for your problem I agree 100% with the mutt.

Frizlefrak · 01-23-2011, 7:05pm

I should have put in my post to watch the fluid level in the master cylinder very closely and don't let it get low. If it runs dry, we start all over AND have to bleed the master.

drmrman · 01-23-2011, 7:19pm

Quote:

Originally Posted by NEVRL8T

My car (1992 auto, 160K miles), at start up, and for a while after that, has a brake pedal problem. It's not the pedal really and I think I know what the diagnosis is probably going to be, but I wanted some opinions. The pedal will go nearly to the floor and I suspect the brake booster is going out. You can pump it up but it will lose pressure quickly. Once it's good and warmed up it will hold pressure pretty well. I had Hawk HPS pads installed in June of 2008 and have maybe 2000 miles on them. There is plenty of brake fluid in the resevoir and the problem started about six months ago. I do not know how to do a brake job so your dealing with a novice here. I have done things like replaced the injectors and I always change my own oil and air filter. I want to tackle bigger projects like changing my heater core, which it needs, and I have an MSD opti and wires ready for when they go. My car has the original opti on it now. So please cut me some slack.

How long is "awhile after" start up? If it a couple of minutes or more I would have to agree with frizzz that it may be a compromised hydralic system... If its only a few seconds after putting the car into gear and moving forward... It may just be the ABS unit needing to cycle... (that wierd buzzing noise that comes from the rear when you put it in gear and start to move forward)

None the less... A brake fluid flush is inexpensive, NOT very difficult, and can only do good

I say give it a shot!

drmrman · 01-23-2011, 7:24pm

Also to add to friz's great explination! When you mighty vac the Master do not suck alllll of the fluid out... because like he said then you need to bleed the master cyl. and that can be annoying...

I personally prefer to gravity bleed majority of the old fluid first then top of the master with new fluid! Gravity bleeding is as simple as opening the farthest bleeder valve (RR) and just letting the fluid flow via the force of gravity... It will take time but during this time you can enjoy 1 or 2 of those beers friz mentioned

C4fan · 01-23-2011, 7:44pm

A helpful hint: Take a 2' piece of 1/4" clear tubing (like on fish tanks) and press it on the bleeder. Then take the other end and run it to a clear plastic bottle. This way your fluid will have a place to go with out making a mess and you can watch the tubing for when the fluid clears up and the bubbles stop.

Frizlefrak · 01-23-2011, 7:53pm

See? Told ya this group knew their stuff.

NEVRL8T · 01-23-2011, 9:15pm

Can someone show me what a "bleeder" looks like on a 1992? I have never messed with brakes in my life. What do I do? Just take the tire off or do I have to remove something else?

NEVRL8T · 01-23-2011, 9:19pm

Quote:

Originally Posted by drmrman

How long is "awhile after" start up? If it a couple of minutes or more I would have to agree with frizzz that it may be a compromised hydralic system... If its only a few seconds after putting the car into gear and moving forward... It may just be the ABS unit needing to cycle... (that wierd buzzing noise that comes from the rear when you put it in gear and start to move forward)

None the less... A brake fluid flush is inexpensive, NOT very difficult, and can only do good

I say give it a shot!

It takes more than 15 minutes.

C4fan · 01-23-2011, 9:42pm

drmrman · 01-23-2011, 10:22pm

Quote:

Originally Posted by NEVRL8T

It takes more than 15 minutes.

Okay then start with bleeding!

Also another hint esp. with a car with as many miles as yours! I would use some sort of penetrating oil (PB blaster or freeze off) to SOAK the bleeders before you try to "crack" them free. AS WELL! I would FIRST use a 6 point socket (I believe 10mm), Then for ease of use, just use a standard style wrench.

Just a couple more tips for you

NEVRL8T · 01-24-2011, 8:46am

Quote:

Originally Posted by Frizlefrak

It sounds like you have air in the lines. Air compresses, liquid doesn't...thus the soft pedal. I would start by fully bleeding the system and in doing so, changing your brake fluid.

Has the master cylinder been off the car? If so, it will need to bled separately.

If not, pick up a couple of big cans of brake fluid, a container to catch it in, a six pack of beer, a helper, and a mighty vac to siphon out the master cylinder.

Siphon out the master cylinder first, and wipe it clean once it's empty. Refill with fresh fluid. Now....there are a number of ways you can do this....speed bleeders, mighty vac, etc....but I prefer to just open the bleeders and have a helper press the pedal while I watch. Start with the wheel that is furthest from the master cylinder (right rear). Open the bleeder, and have your buddy press the pedal to the floor and hold it. Tighten the bleeder, and then have him release the pedal. You will most likely see dirty fluid and air bubbles.....bubbles are bad. Continue doing this until you have clear fluid and NO bubbles. You should be able to finish beer #1.

Once it runs clear and has no more air bubbles, cap it up and move to the next closest wheel (left rear). Repeat on this wheel, opening and consuming beer #2. Once it runs clear and has no air, cap it up. Don't forget to keep checking that master cylinder. It may take several cycles at each wheel to clear the bubbles and old fluid.

Next wheel, right front, and beer #3. After you check the master cylinder and refill, hit the bathroom....you're getting close to being done.

Finish off with the left front, refill the master, and cap it off.

You should now have a firm pedal. If not, something is wrong in the system and needs to be addressed ASAP.

Thanks so much for the info. I am going to try this as soon as I get some better weather. I forgot one thing, what kind of beer should I get?

RedLS1GTO · 01-24-2011, 8:51am

Quote:

Originally Posted by NEVRL8T

Thanks so much for the info. I am going to try this as soon as I get some better weather. I forgot one thing, what kind of beer should I get?

I go with cheap American beer (Bud Light) when working on the cars. That big dollar stuff just doesn't seem to fit in when it comes to smashed knuckles, dirty hands, and cussing.

C4fan · 01-24-2011, 9:31am

Quote:

Originally Posted by RedLS1GTO

I go with cheap American beer (Bud Light) when working on the cars. That big dollar stuff just doesn't seem to fit in when it comes to smashed knuckles, dirty hands, and cussing.

Often times will end up tasting like brake fluid anyway.

drmrman · 01-24-2011, 6:13pm

Not to change the subject at hand because beer is EXTREMELY important... I personaly am a Yuengling fan for the cheap stuff... and a Coorslight fan for the cheaper stuff

But that being said...

Does the pedal feel like you have no power assist... As in No power brakes...? When you push down on the pedal do you have to push extremely hard for the car to stop? If so that may be the booster... Because if it were air in your lines... The squishy or low pedal would not go away after time...

NEVRL8T · 01-25-2011, 8:28am

I have to come clean about something. I don't drink beer. I love Crown and Coke though. I am not to sure I should start on the CnC while messing with my brakes though.

nutz4c4 · 01-25-2011, 2:39pm

Quote:

Originally Posted by NEVRL8T

I have to come clean about something. I don't drink beer. I love Crown and Coke though. I am not to sure I should start on the CnC while messing with my brakes though.

Um,yea. Thats probably a good idea. They always taste better after the job is done...

NEVRL8T · 01-29-2011, 11:39am

Quote:

Originally Posted by drmrman

Not to change the subject at hand because beer is EXTREMELY important... I personaly am a Yuengling fan for the cheap stuff... and a Coorslight fan for the cheaper stuff

But that being said...

Does the pedal feel like you have no power assist... As in No power brakes...? When you push down on the pedal do you have to push extremely hard for the car to stop? If so that may be the booster... Because if it were air in your lines... The squishy or low pedal would not go away after time...

I have to push the pedal almost to the floor for the brakes to engage. The pedal is not stiff at all.

Support the Barn:		Download the Mobile App;		Follow us on Facebook: