Previa brake problems

[elcamino]

I have a 1992 Toyota Previa non ABS with 4 wheel disc brakes at 184,000 miles and have recently experienced brake problems. The brake pedal goes almost all the way to the floor and prior to my bleeding the system the brake light would come on. I went to the military auto craft shop and bled the entire sytem as per the Haynes manual to include the load proportioning valve. This cured the light problem but not the weak pedal. I had the mechanic test drive the car and he suggested that I should replace the master cylinder. The brake pads are fine and there are no leaks nor have I had to add any fluid. I changed the master cylinder and bled the system and still have the same weak pedal with the engine running. The mechanic suggest that I should replace the load proportioning valve. The engine also runs fine when the brake pedal is depressed if it did not he suggest that the booster would be the problem. So before I drop another $100 on parts and my own sweat and blood replacing the load proportioning valve I seek your advice. The Haynes manual said if you having brake problems to have the dealer adjust the valve or replace it. Please help????

[elcamino]

Lot's of readers but no help. What's up. Are there no master mechanics out there???????? Disappointed

[brink]

I dunno what to tell ya besides all the stuff you've tried.

[Rusty]

Recently bought a used '92 Previa LE 2WD. New to the Forum. First Japanese vehicle I've owned. Have to say that we do enjoy driving the "Bubble Van", although the styling is not up to the new ones, (neither is the price) but it does seem to have a niche. Can't say I've heard of a non-ABS 4 Wheel disc, but I would suggest you inspect all discs/calipers for free movement on the pins (sliding bushing) that allow the caliper assembly to "float". You should be able to slide the caliper freely along these pins.

[previa92le]

My 92LE 2WD has 4 wheel discs.

[Passaturbo]

Originally posted by previa92le
My 92LE 2WD has 4 wheel discs.

Same here......disk and shoes in the rear

[Rusty]

elcamino stated they had a "non ABS 4 wheel disc" system. No mention was made about if it was a 2WD or 4WD.

[jwsmsmith]

Brakes, Previa's one weakness. They always need replacing (20,000+ miles). I have a 94 LE 4 disc no abs. Things I have learned from the Toyota shop manual (not Haynes et al.), there are friction points on the calipers and pads that must be lubricated each time you replace pads. The shop manual shows these points. You must use regular lythium soap grease ( the amber colored lythium, hard to find). Use Toyota parts, They are $10 bucks more and include the anti-squeal plates (important for quietness but also must be completely smooth and very flat so they don't start working like springs between the caliper and pad. On the back Emergency brake shoes, separate the activating lever from the rear shoe and put grease on it (on the pivot rod). If you are careful you can reuse the "C" clip. This is very important to the previa brakes even if you don't use your emergency brake as the shoes are only held in place at the top (unlike normal shoes, they "float" and this lever helps keep them centered). Check your rubber hoses. If they bulge in your hand while your partner is stepping on the brakes - REPLACE them. I know - this is a pain. I bought mine in '96 with 28,000 on it and now I have 187,000. Obviously I like it and consider the brakes a small price to pay, (unless you talk to me the day I'm working on them! -Jerry

[deekay140]

you probably got a frozen caliper and or caliper slides,, try pinching off each one of the front brakes hoses (one at a time) and see if u get a better pedal with the hose pinched off.

[adamjt]

Originally Posted by elcamino

I have a 1992 Toyota Previa non ABS with 4 wheel disc brakes at 184,000 miles and have recently experienced brake problems. The brake pedal goes almost all the way to the floor and prior to my bleeding the system the brake light would come on. I went to the military auto craft shop and bled the entire sytem as per the Haynes manual to include the load proportioning valve. This cured the light problem but not the weak pedal. I had the mechanic test drive the car and he suggested that I should replace the master cylinder. The brake pads are fine and there are no leaks nor have I had to add any fluid. I changed the master cylinder and bled the system and still have the same weak pedal with the engine running. The mechanic suggest that I should replace the load proportioning valve. The engine also runs fine when the brake pedal is depressed if it did not he suggest that the booster would be the problem. So before I drop another $100 on parts and my own sweat and blood replacing the load proportioning valve I seek your advice. The Haynes manual said if you having brake problems to have the dealer adjust the valve or replace it. Please help????

Did you figure out the problem? My friends 92 non ABS has the same exact problem and we bleed the brakes like crazy and replaced the master cylinder....still there.

[kanekane]

Hi, I own a 91 Le AWd with 4 disc ABS brake. I had a problem when my father gave me the Previa, it was braking at maybe only 25% from the rear. The Load Proportional valve was so rusted it prevented to add more rear braking (2 brake line go from the Master cilynder to the load proportional valve then 1 to a T to both rear calipers).

So i removed it and bypasssed it with an union, putting a cap on the second brake line. This didn't helped at all, so I biugh a T union and repalced the cap and union by the T. What a difference, now it doesn't drop from the front while braking hard, and rear pads wear much faster (front less)

Kane

[tekmobile]

hello i am havong problem with the rear load valve,, how did you bypass it comment as fait pour faire le bypass??

merci car je suis en train de reparer le mien ,,,il y a une petite crack,, et meme si j ai lubrifié l interieur avec du wd 40 ca marche mieux mais j'aimerais plutot bypasser pour plus de sureté..

merci..

how do you bypass the load sensing brake valve? because its 390$,,,