So I've got an issue with my 94 4x4 22re 4runner. I'm away right now and I'm lending the truck to a friend. It's having an issue where the brake pedal is getting harder and harder to press apparently. So we've narrowed it down to being the brake booster or the brake booster check valve. For me personally both would be pretty easy to do, obviously the check valve being really easy and the booster a little more involved. My friend is not quite as mechanically inclined as I am, but he could probably do the check valve pretty easily. It's killing me to have to pay someone to look at something so simple. I could just tell my friend to park it for the next month till I can get home and then fix it my self....

Is there anyway to easily narrow down between the two? We are pretty certain through fsm tests that it's brake booster system just not sure whether check valve or booster itself.

I could just have him get the valve and try change it, it's probably ten bucks at autozone....

 

Also when I look at the fsm diagram and pictures of my engine bay it looks like the 22re brake booster has a metal inlet for vacuum and then there is an inline bbcheck valve is that correct?

auto parts stores are showing the type that you push in with a rubber grommet to the brake booster.



Circled in red is the brake booster check valve? and that line with red over it is the vacuum line from manifold to brake booster correct?

 

my 1987 has the inline check valve as shown in your photo, but when i looked at a 1994 epc(parts catalog) for a 1994 22RE it showed a check valve/grommet right at the booster

 

A check valve allows air one way only. Verify the check valve by blowing on it both ways. Air should only flow out one side.

Also with my truck (3VZE) if I disconnect my hoses off the check valve this happens:

-hose AFTER the valve comes off like any ordinary hose

-hose BEFORE the valve (entering the valve) is a little harder to come off, and holds pressure it seems. when i take off that hose it kind of sounds like taking an air tool off an air hose (air pop noise)

my breaks work good and have no problems- so i assume the valve is working correctly with that pressure on the inlet hose.

 

Great thank you!

I'm also wondering after talking to a friend thats spent years working on cars if it could possibly be a stuck caliper? I had my friend run the diagnostic from fsm for the brake booster but he's not really that much of a wrench guy. It had been pulling to the right, but I was pretty sure it was from needing an alignment which I can't do till I rebuild the front end.

Could a stuck caliper do the same thing as a brake booster gone bad?

 

To check for a sticky caliper- get the front tires off the ground, spin it and see how each takes to slow down after you spin it. If one slows down way faster, u have a sticky caliper. If its on the rear and it doesnt move at all, take off the parking brake and put it in neutral. While youre there, grab the tire by the top and try to wiggle back and forth to check wheel bearings. Wheel bearings are cheap, even chinese tires are not. (tex-mex, wyndham, wtf?!)

Engine off, press the brake a few times. Should lock up. While holding it, start the engine and the pedal should move. That shows a working booster on most cars

post up your findings

shem

 

Thanks shem, I'm a few weeks out before I can get hands on the truck my self and don't really want to chuck $80 at a mobile mechanic just to diagnose something I can my self. I'll let you all know the verdict when I'm able to!

 

So I’m about 99% its the brake booster. Pedal is really hard to push so braking takes some serious force. When you press the pedal it hisses like leaking air. Also the idle drops to nearly stalling the truck when pressing the brake for long time.

Doing fsm indicates brake booster bad. Checked the inline valve and that is working properly.

Calling parts store they are asking for abs or not and I’m pretty sure it’s not but can’t find any indication (dash lights, printed anywhere in or on truck) etc. that it’s abs.

 

Sounds like the bladder in the booster is bad, wont hold vacuum. On my 90 pu the dash lights show a "rear abs" light w the key on. Either you dont have it or the dash bulb is burned out. Hopefully you can swap it without pulling brake lines off the master, Ive done it on other cars that way when theres room.

Shem

 

Ya that's it for sure! All makes sense now I think it's been slowly going as I've noticed it dropped idle slightly when braking. Found one at Napa for an exorbitant amount (of course) $210 with tax Yikes. Going to pick it up today because I'd rather have it done than stress waiting on shipping. Hoping it's the right one. They say it fits my truck and with no indicators of abs anywhere I'm praying it works. In the pictures it looks pretty much exactly like the one in there now. I guess we'll find out today

There's a pretty good video on youtube about swapping it without disconnecting the brake lines.
I'll post an update later today/tomorrow.

Thanks for the help!

 

Well I did the swap and it went well. Easy enough and there’s no need to bleed brakes. Just disconnect the master cylinder and take a couple bolts out that hold the brake lines in brackets against the firewall. This allows the master cylinder to be clear and just enough room for the old booster to come out. I just matched up the setting for height on the pedal end and the master cylinder end was pretty close to the original so didn’t adjust.

Quick and easy bolt back in and reconnect everything and away we go! Only took about 1.5 hours.

Here’s another video that was helpful


Unfortunately along the way I went to recharge my ac and decided to chase the leak with uv dye. Turns out it’s been leaking from the ac condenser corners. The corners show uv dye and just below that is the front end cross brace. This had some rust and it’s gotten much worse. I had no idea that the ac refrigerant was so caustic that it could degrade metal! Other than a little rust on inside of doors and small spot on chrome bumper (which I see on 90% of 2nd gens in hawaii) this truck is rust free. I’m a little concerned that that cross member rotting out is going to cause some issues down the road. It looks like it would be a bitch to weld a new piece of metal in there too 😖

Hate to let her go but dunno how much more money I can throw at her. Needs u joints, full front end rebuild, exhaust, and now ac condenser, frame work, and i think the heater core is leaking.

Other wise starts and runs like a frigging champ but after doing the clutch, new belts, plugs, radiator flush, brake booster, and new battery this year I’m not sure it’s worth pouring money into.

 

Get another and keep this one for parts/spare/test rig

shem