Brake Pressure Issue

[Nathan Kuwitzky]

I just completed a front axle rebuild on my 1985 FJ60. I replaced the front brake lines, calipers and pads. I bled the entire system starting at the drums in the rear and then the front. The problem is that while driving, when I depress the pedal slowly I don’t have much brake pressure until the pedal is almost at the floor. When I slam on the brakes I get pressure much earlier (about halfway down and feels more normal). Do I have a booster issue? Master cylinder? Need to re-bleed? Any ideas are appreciated. Thanks!

 

[batthewmrown]

There's a section for checking the booster in the FSM. I had a similar issue to yours and after a fell bleed, I just replaced the MC and it all went away.

 

[gt7058a]

Did you empty the master cylinder of fluid? The MC may need a bench bleed.

 

[Nathan Kuwitzky]

Did you empty the master cylinder of fluid? The MC may need a bench bleed.

Did you empty the master cylinder of fluid? The MC may need a bench bleed.

I didn’t touch the master cylinder. Just replaced the brake lines at the front hubs with stainless steel braided lines. I did notice that I had reduced brake pressure shortly before I did the front axle rebuild. I wonder if the master cylinder finally just bit the dust a couple months ago.

 

[gt7058a]

Don’t discount booster as mentioned above.

 

[Godwin]

I have had a couple of master cylinders that presented those symptoms. Gradual braking was soft, almost ineffective but a hard quick mash on the pedal gave better braking. MC replacement cured this both times.

 

[Nathan Kuwitzky]

I have had a couple of master cylinders that presented those symptoms. Gradual braking was soft, almost ineffective but a hard quick mash on the pedal gave better braking. MC replacement cured this both times.

That sounds like exactly what mine is doing.

 

[CenTXFJ60]

How quickly does your parking brake lock in when you pull the handle? I’ve had similar symptoms you’re describing and once I adjusted the rear drums my problem was solved. Simple process but one I overlooked when I replaced the front brakes. Especially if you did not touch the master and not losing any fluid.

 

[Nathan Kuwitzky]

I decided to replace the master cylinder first because it looked original and was inexpensive. I bench bled it and then flushed and bled the entire system once installed. It fixed the problem. The master cylinder was full of sludge. I highly recommend spraying PB Blaster all brake fitting before attempting to remove them. I twisted off one of my hard lines on the rear axle because the fitting was seized to the line and had to fabricate a new one.

 

[Nathan Kuwitzky]

On the road again!!...

 

[Godwin]

On the road again!!...

View attachment 2267262

Next project is to trim the ends of the u-bolts.

 

[Nathan Kuwitzky]

Next project is to trim the ends of the u-bolts.

Hahaha! Good eye!!

 

[atx88]

I had a similar issue which was cured via replacing the brake master cylinder. I’ll go through my scenario to help others with similar symptoms....

I recently purchased a FJ60 after wanting a Landcruiser for years. Immediately took it, via a tow, to my local shop after purchasing since the alternator died on the drive home. Had a fair amount of additional work done, biting the bullet since I have absolutely zero mechanical experience. Landcruiser Specialists had it running nice and smooth for me after a full run through. About 200 miles after getting it back the brake light went on and stayed on. Not knowing any better, I thought the brake light was merely and indicator of whether or not the parking brake is on/off, and was oblivious to the idea it could also be warning of low fluid or pressure in the brake system (I think?). Yeah, when I say zero mechanical experience I meant it literally. Anyways, some time after the brake light flips to always on (maybe another 100 miles) the brake pedal goes super soft and has to be pressed nearly to the floor before anything happens. Brakes still worked but pretty sketchy with very little power, and only after a looooong press on the pedal. The parking brake was fine.

After seeing a few other threads the brake master seemed like a likely culprit and a relatively easy fix. I went with the new Napa brake mastery cylinder as others suggested. Very satisfied with this product, it appears to be identical to the OEM it replaced, and only $70. Loosening the brake lines from the master was tedious but manageable. Liberal and frequent applications of knock‘er loose helps, and I also used some groove lock pliers to clamp over the wrench to prevent slipping. I highly recommend doing both if your lines are potentially seized or rusted on.

The upper bolts to remove the brake master are easy to get off, but one or two of the lowers are best accessed with an offset wrench. After getting stuck here I picked up this set from Amazon which is an awesome value and high quality. Bench bled the master using trigger clamps which was an absolutely fine substitute for a vise. Bolted the new master on along with the original LSPV, and after getting the hoses back on a friend helped me bleed the brakes.... and then good as new! Brakes are firm and flawless now. Thanks to all the info here that made this possible!

 

[NearJetties]

I have a wonky braking issue I’ve been trying to fix so piling on here. I replaced the master cylinder with an Aisin/OEM unit which I bench bled but couldn’t get it to work no matter how much I bleed the brakes (followed FSM). Turns out the new booster was bad.

Replaced the master with a good unit and braking is good. Not quite as good as I think it should be but acceptable. In the process I ended up putting on new reman calipers (Napa eclipse) and new Aisin pads.

The problem is I have brake drag now that won’t go away no matter how the brake booster pin or the pedal play is adjusted. It’s not enough to really feel resistance or cause a pull when driving.

However, if you spin the wheel by hand when it’s up on jacks you can feel it and it causes a whirring sound above 25mph (so annoying). The passenger front seems worse.

It doesn’t build heat, the rear drums spin freely, and based on the parking brake takes 7-11 clicks to engage (which is the FSM spec). The booster passes all tests I’ve thrown at it. I even replaced the passenger front caliper on warranty thinking it was sticking.

In the process of trying to determine what turned out to be the bad new master I pinched the brake lines to try to isolate the a potential problem as recommended a few places. Maybe I killed them and it’s not allowing the pads to suck in enough with the foot off the brake.

I have new front brakes lines to put on next. Will this fix my problem?

 

[Michael Hanson]

Hi, Do you have the anti rattle W clips on the brake pad pins? Mike

 

[Seth S]

For future reference there is no need to bench bleed the MC in a 60. Just the normal bleeding process will adequately bleed the MC, lines, and calipers/pistons.

 

[NearJetties]

Hi, Do you have the anti rattle W clips on the brake pad pins? Mike

I have the ones in that came in a kit with the reman calipers installed (pic below) as the diagram shows as far as I can tell. Rotors were in spec thickness wise.