*#%^($@ BRAKES! (1 Viewer)

[Azca]

MUD braintrust.

Okay, I need ideas. Brakes stopped working last week. Brake pedal had normal pressure but would not stop, well not till after midway through a very busy intersection on a red light on the way back from the hospital. Tear everything apart and right the rear inboard pad was almost worn to the metal, all others at about 30 - 50% after 40k miles.

I needed to resurface the front rotors anyway so ("warped rotors"), so I had bought the Powerstop package a month or so before all of this happened. While I was at it, I also replaced all the soft lines as well as the master cylinder as they were old and needed to go. Lines were Toyota, courtesy of Murf and friends, with lengthened lines per smittycrusher's post: OEM Extended Brake Lines w/ part numbers

Also did the LSPV delete per excessive's post: Mudders hate him! 1 weird trick to fix the LSPV

So perhaps I should have done this a step at a time but, this last two weeks have been nothing short of exhausting dealing with a multitude of real and imagined emergencies. I needed to get this rig back on the road as next week we are trying to clean up the real emergencies from last week. Next weekend is out of the question for working on the rig due to the emergencies.

So here I am, have bled two quarts through the beast using a vacuum bleeder and the two person method and still a soft pedal. I am thinking there may be a leak somewhere but not sure how to find it.

Any suggestions ?

 

[plutonius]

If everything else looks good (ie no seized calipers, brake booster is ok, master cylinder is ok, and no leaks) try bleeding with the truck nose high, and then move it, pointed down a steep hill, and bleed with the nose down. I recently rebuilt my front calipers, and could not get rid of the soft pedal until I took this approach. It seems that with the nose down there are bubbles in the lines that manage to work themselves out.

 

[ajax1]

I always gravity bleed the system seems to work best , I assume you bleed the master before putting it on? I also smack the calipers with a rubber mallet after bleeding one to knock any air up to the top, then bleed again

 

[Azca]

Did not bleed the master, thought about it but the FSM did not indicate a need so just used the vacuum pump.

 

[jfz80]

A new master install should be nench bled first to get majority of air out.

Have you cycled abs between bleedings?
Take it out and lock up the brakes in some gravel a few times to purge air from abs.

The one worn pad sounds like a separate issue of a sticking caliper piston. Rebuild or rebuilt are both options, id opt for the latter having done the former. Also make sure to lube the slide pins.

 

[ajax1]

You need to bench bleed the master to get air out of it, if one caliper is eating pads then it is sticking , you can get a Napa eclipse brake calipers that are black and are rebuilt Toyota calipers

 

[shocktower]

I , never ever resurface, just new pads, and or rotors, resurfacing is BS, and you will never get the warp out that way, haul ass and clamp on the brakes hard, if you don't have ABS, also doing a bleed you need to bleed the LPVS, I used a home made pressure bleeder cost me about $15, I have done them the vacuum and the 2 man bleed, I learned about this system from a BMW mechanic, and you can do it solo. if you want more info PM me

 

[Red Merle]

I , never ever resurface, just new pads, and or rotors, resurfacing is BS, and you will never get the warp out that way, haul ass and clamp on the brakes hard, if you don't have ABS, also doing a bleed you need to bleed the LPVS, I used a home made pressure bleeder cost me about $15, I have done them the vacuum and the 2 man bleed, I learned about this system from a BMW mechanic, and you can do it solo. if you want more info PM me

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Please share that here. I would love to see how you rigged that up and how it works. I am sure others would as well. I was going to buy a miti-vac so I could bleed brakes alone, but I already have that model garden sprayer that I originally bought to spray oil on the underside of my truck. That doesn't really work very well so I cleaned the sprayer out and now it's just sitting there.

 

[Azca]

A new master install should be nench bled first to get majority of air out.

Have you cycled abs between bleedings?
Take it out and lock up the brakes in some gravel a few times to purge air from abs.

The one worn pad sounds like a separate issue of a sticking caliper piston. Rebuild or rebuilt are both options, id opt for the latter having done the former. Also make sure to lube the slide pins.

I don't dare take it out now, she has no brakes, it goes all the way to the floor.

I need to bleed the MS. Not sure what I was thinking, well actually, I wasn't. This is not my first rodeo but thought I might be able to get it done with the vacuum pump. Can't fix stupid - but you can sure pay for it. I even bought a bench vise just to bleed it but no, drop pants, insert head... Just too much stuff going on and rushed. Should not work on such an important system with so much on your mind.

 

[Azca]

I , never ever resurface, just new pads, and or rotors, resurfacing is BS, and you will never get the warp out that way, haul ass and clamp on the brakes hard, if you don't have ABS, also doing a bleed you need to bleed the LPVS, I used a home made pressure bleeder cost me about $15, I have done them the vacuum and the 2 man bleed, I learned about this system from a BMW mechanic, and you can do it solo. if you want more info PM me

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Just sent you a PM. Looks interesting, just need to watch the fluid levels, right?

 

[Tools R Us]

You need to bench bleed the master to get air out of it, ...

Have installed many masters and don't recall the last time I did a bench bleed, likely decades ago. It can reduce bleed time, maybe, but when installing, fluid runs out, air goes in, makes a mess and IMHO doesn't make much difference. Once the master is installed, fill and rapidly short stroke the pedal until some pedal resistance is felt, then start at the bleeders.

 

[Tools R Us]

I , never ever resurface, just new pads, and or rotors, resurfacing is BS, and you will never get the warp out that way,

So by mounting an object in a lathe and cutting it wont remove run-out, so mankind has been doing to wrong for centuries? On a floating pad system like this, within reason rotor run-out will not cause brake judder. It's caused by thick spots in the rotor, most often from uneven pad material deposited on the rotor. Run-out will knock the pads back, causing more pedal travel, like loose wheel bearings. In most cases, new rotors, hub mounting surface are not perfectly straight, some don't torque mounting bolts, so most new rotors have run-out, some is allowable. When I did brakes all of the time, we cut every new rotor to make them straight to the hub/bearings, this is the best method.

I used a home made pressure bleeder cost me about $15, I have done them the vacuum and the 2 man bleed, I learned about this system from a BMW mechanic, and you can do it solo. if you want more info PM me

Not new, search google for; garden sprayer brake bleeder. Have used most type of bleeders, now just do the pump and release. Bleeders are great if you do brakes all of the time, if not are more work/mess than it's worth and wasteful. The fluid is hygroscopic, so should not be stored in them, whatever isn't used should be disposed of.

The '80 system is relatively large capacity, so takes effort, but isn't all of that to do. The two main mistakes that I have seen: Overly aggressive pedal pushing, foaming, entrapping air in the fluid. Should be done relatively deliberately, using normal use pedal pressure. Bleeder valve should only be opened when the system has pressure, and closed before it over, still is flowing.

The procedure we use when a system has been empty, hydraulic parts have been changed. First short stroke the pedal a couple dozen times. Slightly open a bleeder valve, put a finger gently over it to make a one-way valve, have the helper full stroke the pedal until fluid starts coming out. Repeat at each bleeder. Now should have some pedal, start at the first bleeder and do the three pumps and release thing. Pedal pushing should be like normal driving, excessive pressure, slamming the pedal is not productive.

Have done this many times, with 100% success, don't see why some have so much problem with it. Still have one, but this can be done quicker than setting up and dealing with a power bleeder, so never use it.

 

[flintknapper]

Unfortunately, I've found the 80 series to be a most difficult system to bleed. When installing a new master cylinder is a good idea to bench bleed it first (whether or not it is called for in the FSM).

From the sounds of it....you likely have air in the Antilock system and in the LSPV.

I always gravity bleed first, then hook up my 'pressure' bleeder (don't like vacuum bleeders) to the system. Bleed the system. Go find a surface with poor traction (gravel, sand, grass) and lock up the brakes (activating the ABS) 8-10 times. Come back and re-bleed paying attention to the LSPV (air loves to accumulate there).

As for vacuum bleeders, they simply don't draw fluid through the system forcefully enough to move air bubbles from certain areas. You would do better to use the old 'two man' method of pump up the pedal and open the bleeder screw, or use a pressure bleeder.

Just my .02 on it.

Flint.

 

[NLXTACY]

Years ago I used to bench bleed masters because that's how I was taught. Today I don't bother. I bleed my brakes constantly and cycle the ABS to get every bit of air out. I also don't let the brake fluid stay longer than a year. All of this has never given me a reason to curse my brakes.

 

[Pin_Head]

Have installed many masters and don't recall the last time I did a bench bleed, likely decades ago. It can reduce bleed time, maybe, but when installing, fluid runs out, air goes in, makes a mess and IMHO doesn't make much difference. Once the master is installed, fill and rapidly short stroke the pedal until some pedal resistance is felt, then start at the bleeders.

X2

I have installed hundreds of master cylinders and didn't bench bleed any of them. The few that needed bleeding we did in the car. A trick is to cover the master with a plastic bag to keep the fluid from getting all over in the engine compartment and putting your fingers over the outlets to act as one way valves to let the bubbles out without letting bubbles getting sucked back in.

 

[nukegoat]

The brakes on the 80 are mediocre to begin with

 

[Azca]

Can the ABS be bleed electronically on these rigs?

 

[nukegoat]

Can the ABS be bleed electronically on these rigs?

Ostensibly

 

[shocktower]

So by mounting an object in a lathe and cutting it wont remove run-out, so mankind has been doing to wrong for centuries? On a floating pad system like this, within reason rotor run-out will not cause brake judder. It's caused by thick spots in the rotor, most often from uneven pad material deposited on the rotor. Run-out will knock the pads back, causing more pedal travel, like loose wheel bearings. In most cases, new rotors, hub mounting surface are not perfectly straight, some don't torque mounting bolts, so most new rotors have run-out, some is allowable. When I did brakes all of the time, we cut every new rotor to make them straight to the hub/bearings, this is the best method.



Not new, search google for; garden sprayer brake bleeder. Have used most type of bleeders, now just do the pump and release. Bleeders are great if you do brakes all of the time, if not are more work/mess than it's worth and wasteful. The fluid is hygroscopic, so should not be stored in them, whatever isn't used should be disposed of.

The '80 system is relatively large capacity, so takes effort, but isn't all of that to do. The two main mistakes that I have seen: Overly aggressive pedal pushing, foaming, entrapping air in the fluid. Should be done relatively deliberately, using normal use pedal pressure. Bleeder valve should only be opened when the system has pressure, and closed before it over, still is flowing.

The procedure we use when a system has been empty, hydraulic parts have been changed. First short stroke the pedal a couple dozen times. Slightly open a bleeder valve, put a finger gently over it to make a one-way valve, have the helper full stroke the pedal until fluid starts coming out. Repeat at each bleeder. Now should have some pedal, start at the first bleeder and do the three pumps and release thing. Pedal pushing should be like normal driving, excessive pressure, slamming the pedal is not productive.

Have done this many times, with 100% success, don't see why some have so much problem with it. Still have one, but this can be done quicker than setting up and dealing with a power bleeder, so never use it.

Yes Google does have that, and storing it in it is a bad idea, but doing things alone when you need help, this is great, and when you use one very to little or zero pedal, and setting up a power bleeder is so easy. 1 fill tank and put pump handle on pressure bleeder 2 put MC cap that is attached to pressure bleeder to MC tighten hose clamp 3 pump handle a few times 4 start bleeding brakes 5 brake job is done. I guarantee I by myself can beat you and another person doing it the old way, I have done them vacuum and old school way, a pressure bleeder is the new way, I know some people do not like change, but some times changes are good just my .02

 

[Stevesnj]

If you have an air compressor use one of these, it will pressure bleed through the ABS system too. Been using for years and works amazingly well. Never had any bubbles or air trapped. ABS works fine. Have done about 5-6 bleeds with this this. Never a problem.

Pneumatic Brake Fluid Bleeder