Intermittent Power Brakes

[OilInTheGas]

I've got a '97 LX450 and once in a while when I push the brake pedal it is hard and has no power assist. If I keep applying pressure to the pedal the power assist comes back. This seems to have no rhyme or reason and is hard to reproduce the problem. Has anyone experienced this before? I'm assuming its a bad brake booster but I've never seen one fail then work again right after.

 

[richardlillard1]

That’s what my brake booster did when it was taking a dump. It will get worse and then fail completely.

 

[jonheld]

Yep. Brake booster. Possibly the vacuum valve and grommet mounted in the booster.
Make sure all your vacuum lines are in good shape before replacing parts.

 

[mdawg]

^ x3

I had the same problem a couple of years ago... replacing the brake booster fixed it.

 

[OilInTheGas]

Thanks for the confirmation guys. The lines look good and the check valve appears to be working correctly.

 

[jonheld]

the check valve appears to be working correctly.

How did you test it?

 

[OilInTheGas]

How did you test it?

I placed a hose on the end of the valve and just sucked on the hose then tried to blow into it.

 

[OilInTheGas]

I replaced the booster with one from a wrecking yard. I took it to the snow and had no trouble all day. Out of curiosity I took apart the old booster and found a tear in the rubber diaphragm. Problem found and solved. Thanks Guys!

 

[beachpirate]

How hard was it to do this work yourself? I don't have a manual yet for my '94 FJZ80 and I'm having an issue where about once a week the brakes are hard as a rock for about a sec. So far it has only happened when I've been idling, going less than 5mph, and no one has been in my path because there is no way I could stop it if I wanted. If I let go and then touch the gas for 1/2 a sec and then go back to the brake it is normal.

My mechanic says he can't find anything wrong with it, but after reading all the posts here I suspect the brake booster so I might just replace it myself.

 

[Sc0-]

That's what my brakes did before losing power brakes... Think it took two weeks to completely go TU.

Replaced it with a Seikens OEM unit, didn't need to lift the engine to replace it. Power brakes restored, hopefully for another 24yrs of service...

 

[OilInTheGas]

How hard was it to do this work yourself? I don't have a manual yet for my '93 FJZ80 and I'm having an issue where about once a week the brakes are hard as a rock for about a sec. So far it has only happened when I've been idling, going less than 5mph, and no one has been in my path because there is so way I could stop it if I wanted. If I let go and then touch the gas for 1/2 a sec and then go back to the brake it is normal.

My mechanic says he can't find anything wrong with it, but after reading all the posts here I suspect the brake booster so I might just replace it myself.

I was having the same issue as you are now. It took me about an hour to replace the brake booster. IIRC it's 4 nuts to remove the master cylinder from the booster and a bracket, then gently pull it apart trying not to bend the hardlines too much. Then crawling under the dash and unbolting the booster from the firewall and disconecting brake pedal from plunger rod. There is room to wiggle the booster out without removing anythng else. I'm cheap and this is just a weekend play vehicle so I bought a used booster from a wrecking yard for like 60 bucks. So far so good.

 

[beachpirate]

I was having the same issue as you are now. It took me about an hour to replace the brake booster. IIRC it's 4 nuts to remove the master cylinder from the booster and a bracket, then gently pull it apart trying not to bend the hardlines too much. Then crawling under the dash and unbolting the booster from the firewall and disconecting brake pedal from plunger rod. There is room to wiggle the booster out without removing anythng else. I'm cheap and this is just a weekend play vehicle so I bought a used booster from a wrecking yard for like 60 bucks. So far so good.

hmm....guess what I'll be doing next weekend or the one after.

 

[beachpirate]

Seikens OEM unit

I did a google search for this type of brake booster and came up empty. Are you happy with it (was it painted?) and where did you get it?

 

[OilInTheGas]

I did a google search for this type of brake booster and came up empty. Are you happy with it (was it painted?) and where did you get it?

It was just pulled from what I assume was a wrecked FZJ80. It wasn't rebuilt or anything after. Used OEM Toyota Auto, Truck and Suv Parts Recycling they are local for me so I just walked in.

 

[Tools R Us]

I did a google search for this type of brake booster and came up empty. Are you happy with it (was it painted?) and where did you get it?

What kinda car do you have? For the 1FZ, '80, try google, Seiken W0133-1740427

 

[beachpirate]

What kinda car do you have? For the 1FZ, '80, try google, Seiken W0133-1740427

1994 FJZ80

I think this will do for ~$180 from A1 Cardone 94 1994 Toyota Land Cruiser Brake Booster - Brake - A1 Cardone, Centric, Genuine, Seiken - PartsGeek

 

[-Spike-]

1994 FJZ80

I think this will do for ~$180 from A1 Cardone 94 1994 Toyota Land Cruiser Brake Booster - Brake - A1 Cardone, Centric, Genuine, Seiken - PartsGeek

Same part on Rock Auto for ~$150

Shipping/tax may be different.

 

[Tools R Us]

Among the reman units, have had the most problems with Cardone, less with Centric, but mine and couple of others make a whistle. Next time will get a new Seiken unit.

 

[beachpirate]

Did the work to replace the brake booster on Sunday and it was fairly straight-forward. Only thing that took me a few minutes to figure out was how to get it out around the intake manifold. A small amount of convincing with a bar and it was right out. For a noob like me it took 2 hours (including water breaks since it was 102F out) from the time I started until I had the refurb one in and was testing by driving around the block.

Thanks for the help everyone, and it's stopping correctly so far!