Dragging brakes

[hammerheadfistpunch]

Now we are talking problem, does it still do that?

No, that was 100% fluid contamination eating seals. I went to moab to do lockhart basin only to have my brakes go full lockup. After talking to them on the phone they told me their supplier accidentally put ps fliud in their brake flush tank and even though it was cleaned out it must have contaminated the system. The seals were so swollen you couldn't force the caliper pistons back into the caliper with a vice grip. Rock hard pedal, full brakes.

A shop down there replaced the MS and flushed the system and I made it through the basin and back home but on the drive home anything over 50 and it felt like I lost all my wheel weights. it was also doing this on the way down to a lesser degree. When I got back they tore it all apart and put in new stuff (minus the reused lines and res.) and it was smooth sailing at any speed for a few weeks then it came back. They replaced the MS and res again and smooth sailing again but its starting to show again.

I've also noticed that turn in elicits more tire scrub than before...as in some where none should exist, meaning either the driveline is binding or there is a resistance force on the tires causing the slower wheel to bit a little and scrub (brake drag).

 

[hammerheadfistpunch]

No, that was 100% fluid contamination eating seals. I went to moab to do lockhart basin only to have my brakes go full lockup. After talking to them on the phone they told me their supplier accidentally put ps fliud in their brake flush tank and even though it was cleaned out it must have contaminated the system. The seals were so swollen you couldn't force the caliper pistons back into the caliper with a vice grip. Rock hard pedal, full brakes.

A shop down there replaced the MS and flushed the system and I made it through the basin and back home but on the drive home anything over 50 and it felt like I lost all my wheel weights. it was also doing this on the way down to a lesser degree. When I got back they tore it all apart and put in new stuff (minus the reused lines and res.) and it was smooth sailing at any speed for a few weeks then it came back. They replaced the MS and res again and smooth sailing again but its starting to show again.

I've also noticed that turn in elicits more tire scrub than before...as in some where none should exist, meaning either the driveline is binding or there is a resistance force on the tires causing the slower wheel to bit a little and scrub (brake drag).

EDIT: I notice when things are good there is very little shunt, but as it get worse my shunt gets bad.

 

[shocktower]

Check both drive lines, take each caliper off, and see if you can, push all of the pistons in, there some times are just bad calipers, trust me I have more bad luck than good, next the Flux capacitor LVPS or what ever that dam thing is called. And also make the shop give you every dollar back, since the Effed up the sytem and bill them for the cluster

 

[shocktower]

Also check wheel bearings SMH thinking about butchers

 

[hammerheadfistpunch]

Check both drive lines, take each caliper off, and see if you can, push all of the pistons in, there some times are just bad calipers, trust me I have more bad luck than good, next the Flux capacitor LVPS or what ever that dam thing is called. And also make the shop give you every dollar back, since the Effed up the sytem and bill them for the cluster

I think about the caliper bad issue but the tempa are normalized across all 4 rotors and so i dont think its a bad piston (have had one of those) i thought about wheel bearings but the hubs are cool and there is no play.

Driveline? Could be, but what, where and how? There is a lot that goes into "driveline"

 

[Red Merle]

I still think after 6 master cylinders that you should check to be sure the push rod on the brake booster is in spec with the master cylinder. Figuring out how far the push rod is sticking out is admittedly one of the most frustrating jobs on these trucks that I have run across, but man, that thing has to be spot on. If its even 1mm out of alignment, it's too far. Some of the aftermarket parts have different depths on the master cylinder end of it and it just goobers everything up. I got lucky when I bought my last booster because it was miraculously set to factory specs and I had a refurbished OEM master to plug it into.

Prior to that, I was having all sorts of trouble with my brakes, even after deleting the LSPV and the ABS unit. Once I got them bled and the right booster in there with the right adjustments, my stuff was tight. I was surprised how nimble and responsive it was compared to some of my other Toyotas and for sure all of my old American SUV dreamboats were. My '73 Wagoneer was a stout truck, but it had rear drums and underbuilt discs in the front. I could slow it down, but full stops weren't it's strong suit. The 80 can be much better than that, you just have to tune what they put on to accommodate US safety laws and the like for that time period. The 80 really doesn't need all of that stuff and in most of the rest of the world, they don't have it. Same with the EGR system and a million other things. Just check that gap out.

 

[hammerheadfistpunch]

I still think after 6 master cylinders that you should check to be sure the push rod on the brake booster is in spec with the master cylinder. Figuring out how far the push rod is sticking out is admittedly one of the most frustrating jobs on these trucks that I have run across, but man, that thing has to be spot on. If its even 1mm out of alignment, it's too far. Some of the aftermarket parts have different depths on the master cylinder end of it and it just goobers everything up. I got lucky when I bought my last booster because it was miraculously set to factory specs and I had a refurbished OEM master to plug it into.

Prior to that, I was having all sorts of trouble with my brakes, even after deleting the LSPV and the ABS unit. Once I got them bled and the right booster in there with the right adjustments, my stuff was tight. I was surprised how nimble and responsive it was compared to some of my other Toyotas and for sure all of my old American SUV dreamboats were. My '73 Wagoneer was a stout truck, but it had rear drums and underbuilt discs in the front. I could slow it down, but full stops weren't it's strong suit. The 80 can be much better than that, you just have to tune what they put on to accommodate US safety laws and the like for that time period. The 80 really doesn't need all of that stuff and in most of the rest of the world, they don't have it. Same with the EGR system and a million other things. Just check that gap out.

I agree with the importance but it's a new factory booster and factory (aisin) Ms and through all the ones they've put on they claim it's perfectly aligned. It could be that since there is no adjustment they are doing "close enough" so they don't have to add or subtract material but the shop in Moab said the one they put in the was spot on (another aisin) and they made a huge deal about it to the point of making sure to let me know they would weld or grind as needed to ensure a perfect fit.

I haven't done it myself so I can't say... Has anyone had to add or grind to get their factory parts or factory replacement to work? (Seriously asking) I know the fsm makes a specific point about it.

 

[Red Merle]

I agree with the importance but it's a new factory booster and factory (aisin) Ms and through all the ones they've put on they claim it's perfectly aligned. It could be that since there is no adjustment they are doing "close enough" so they don't have to add or subtract material but the shop in Moab said the one they put in the was spot on (another aisin) and they made a huge deal about it to the point of making sure to let me know they would weld or grind as needed to ensure a perfect fit.

I haven't done it myself so I can't say... Has anyone had to add or grind to get their factory parts or factory replacement to work? (Seriously asking) I know the fsm makes a specific point about it.

The booster rod is threaded. If the booster is holding vacuum, you should be able to push a bit on the plunger so that you can get the push rod all the way out. Then you have to measure it somehow. Search for that. There are some factory service bulletins that I may have saved somewhere. Not going to lie, it's not easy. If the factory unit was refurbished, it's entirely possible that the the rod got bumped off by a few thread turns. It's that picky. I went through 3 boosters until one just clicked. It was like night and day, immediately. I had everything bled and tight through the MC. I just pulled the booster and swapped it until I found one that worked. Probably four or five tries, total.

 

[shocktower]

I think about the caliper bad issue but the tempa are normalized across all 4 rotors and so i dont think its a bad piston (have had one of those) i thought about wheel bearings but the hubs are cool and there is no play.

Driveline? Could be, but what, where and how? There is a lot that goes into "driveline"

Both drive shafts

 

[hammerheadfistpunch]

Both drive shafts

I've been keeping a close eye on those. They are fine. Ujonts are less than 50k, fully balanced, angles are good, slip joint is good. I pulled both not not ago just to eliminate them as a culprit in another issue. They are great.

 

[shocktower]

I reread you fiasco, and I would be Leary, of that shop ( their vendor put the wrong fluid in the tank WTF ) is this shop like oil can henry's where they need that much brake fluid stored, I know I go through a bit of it, and if I opened a quart and don't use it in a month, I get a new one, I am not trying to be a richard head but the clowns really screwed the pooch, and I am glad you did not get hurt, or hurt another person, because of their cluster, I know when you get an OEM MC it has the reservoir on it, and what calipers did these guy's put on. If you have a wheel/brake still dragging they did not do a correct job. I hate paying for people to do things I can, and rarely trust anyone to work on my vehicles, you may need to go back and ask goober what he really did to your vehicle

 

[mudgudgeon]

I've been keeping a close eye on those. They are fine. Ujonts are less than 50k, fully balanced, angles are good, slip joint is good. I pulled both not not ago just to eliminate them as a culprit in another issue. They are great.

50k miles is potentially a lot of miles on uni's, particularly if your doing hard wheeling with it.
I've had cheaper uni joints s*** the bed within months. I try to stick with Toyota uni joints. Costs nothing to pull drive shafts out and check the uni joints
Same with checking the push rod

IF fluid contamination has affected rubber hoses, I'd be stripping calipers and putting new seals in, same with LSPV.
Caliper seals are cheap, and easy to change. It's the breaks bleed after that sucks.

 

[hammerheadfistpunch]

50k miles is potentially a lot of miles on uni's, particularly if your doing hard wheeling with it.
I've had cheaper uni joints s*** the bed within months. I try to stick with Toyota uni joints. Costs nothing to pull drive shafts out and check the uni joints
Same with checking the push rod

IF fluid contamination has affected rubber hoses, I'd be stripping calipers and putting new seals in, same with LSPV.
Caliper seals are cheap, and easy to change. It's the breaks bleed after that sucks.

They are Toyota EOM ujoints and it was put together by a driveline specialist. I took both shafts off not long ago and inspected for play and wear and there is none.

Since the contomination there is all new brake system components minus the hoses. Booster to calipers. Not sure what the calipers are though.