fishon1213

I recently purchased a 1985 4runner. The truck has only 81K but will need some work because it sat for 10 years. The brake pedal is firm but I really need to press it hard to get the truck to stop. I definitaly cant lock up the wheels. I am pretty sure I need to replace the brake booster. In order to replace the brake booster it is pretty much bolt in right? I don't need to mess with any open lines or anything right. Also, what brake boosters will work? How about one from an '88 V6? Thanx, AL

myyota

Yes, you can replace the booster with out taking any lines loose. I would recomend you upgrade to a duel diaphragm brake booster, it will improve your braking. I added a duel diaphragm booster to my 85 toyota 4x4 truck with 37" tires and it made a noticable improvement in braking.

fishon1213

So will a brake booster from any years(84-88) work as well? Does it need to be from a 4 cyl? I found one from a 88 with a v6, would this be dual diaphram?

myyota

It should work, you can tell the difference between the duel diaphragm and the stock booster, the duel diaphragm booster is about 1" thicker in the front. the stock booster is more rounded in the front.

scmedic

Where did you find an 85 with only 81K? Sweet find! Any pics you can post?

The brake booster is a strait forward replacement - just disconnect 4 bolts on the firewall, the brake pedal pin connection, and the master cylinder. You might have to bend the MC brake lines a little if you don't want to disconnect them in order to clear the booster's push rod.

If you haven't already done it, one diagnistic test you can do to check the operation of the brake booster is to disconnect the vacuum line to the booster (you'll need to plug it up on the throttle body side to keep the engine running) and see if there is any difference in the brake operation or pedal feel.

If the truck has been sitting for 10 years might also be a good idea to flush the brake lines and check the operation of the master cylinder, calipers, and wheel cylinders (if you haven't already done so).

fishon1213

Sorry I don't know how to post a bigger pic. It was sitting behind a mechanics shop for the past 10 years. I tried to buy it off him about 5 years back but he wouldn't go for it. He finally sold it to me a few weeks ago. Needs a lot of work. Having some problems with the valvetrain, brakes suck, needs exhaust work, little bit of cancer. All in all not bad. Back window works, suspension is good, steering is tight, shifts well and 4wd works great!

fishon1213

here's the pic

scmedic

Nice looking truck - good find for you!

waskillywabbit

iTrader: (-1)

Pirate4x4.com 4Runner Pickup forum

Toyota FAQ thread at the top has the years that will fit

Richredneck989

Based on my recent experience with brakes...

In addition to checking all hydraulic components (master cylinder, wheel cylinders, calipers) and definitely flushing the fluid, more then once and in the proper order. It took me a great deal of time and effort to get ‘clean’ fluid at all 4 wheels and LSPV.

I would also take a close look at the rubber lines for condition, have someone push the pedal hard while watching each one, watch for bulges and damp spots indicating tiny leaks. Take a good look at the rear shoes as a bad seal can contaminate them and render them useless, also check the fronts for contamination.

In my case almost all components were bad so they all got replaced and after wrestling with the LSPV for a week I got it working properly again. Truck will stop on a dime but still has the old, single diaphragm, booster even though I did upgrade to ‘v6’ fronts and MC. We will replace the booster soon though.

Good luck and I hope that something here helps.