I have a 96 4runner Limited Edition. When I step on the brake pedal below 40mph, it feel very spongy. I have to slowly step on the brake pedal almost half way to the floor in order to feel some braking power.

When I drive the car on the freeway at high speed and step on the brake pedal, it doesn't feel spongy and stops good.

I have bleed the system threes time and followed the instructions I got from Yotatech forum.

I know 96 4runner doesn't have a perfect brake system, but my brake systems is beyond reasonable performance.

Any ideas??????? Thanks.

 

I think you better check out your master cylinder/ vacuum booster. I'll bet the MC is about to go.

 

Here's an easy test.With the engine running (in park/neutral)slowly press the brake pedal down.If it goes to the floor your master is bad.

 

Thank you for your suggestions. I have test the brake padel as you suggestted and the brake padel almost reach the floor.

Is is easy to change master cylinder/ vacuum booster? Is there a special tool that I need to do it?

I am a weekend mechnics level.


Thanks,

 

no the master is easy, just use something to cover the paint cuz brake fluid eats that stuff away.

 

I replaced the MC and power bleed all four wheels and the brake padel still soft like before. Before I start to replacing rear wheel cylinders and I want tomake sure I bleed the LSPBV.

Does 1996 Toyota 4runner Limited Editon have a load sensing proportioning and bypass valve? I have manual but it is for both Tacoma and 4RUNNER and it indicates that I have to bleed the load sensing proportioning and bypass valve.

I check under the rear of my 4runner and I can't find it.

Thanks,

 

I don't think you have a LSPV. Only the Taco's had that.

 

Thanks for your reply. I have changed out the Master Cylinder and bleed all four brakes with two friends and the pedal still very soft like before.

I checked all four brakes and there is no visible leak. What else do you think can cause this soft brake problem?

Here are few thing I am sure I did correctly:
Bleed all four brakes
Master Cylind bench bleed
No visible brake fluid leak anywhere


One thing is I think could be something wrong is that the rear passenger side brake always takes three or four time to get the air out. First time you think all the air is out, then you go back bleed, the air still exsist. So I did four time. I checked around the fitting, there is no visible brake fluid leaks out. Something could be wrong with it, I am just not sure what.

 

how did you bleed the system? what method?

 

I tried pedal push first, then used a electric vaccume system. It connects to a brake fitting and sucks out the brake fluid.

The Master Cylinder I purchase from my local auto store is a OEM rebuild. Do you think I could have damaged again by use pedal push method the first time bleeding?

Thank you very much for your help.

 

Technically, you are supposed to bleed the drivers rear, pass rear, pass front, drivers rear (in that order). Did you do that?

Did you put a block under the brake pedal when you bled the brakes?

 

I didn't follow that order. I am gonna do it again and I will also put a block under the pedal too. Thanks.

 

I bleed the brake again at this order driver side rear, passenger side rear, passenger front, driver side front.

I got all the air completely out at driver side rear, passenger front, driver side front.

The passenger side rear is the problem, no matter how many time I bleed, there is alway little air in there. I check everywhere but there is no leaking anywhere. Should I just change out the wheel cylinder for passenger rear?

What else I should check besides keep bleeding brakes? Thank you.

 

Double check the line near the passanger rear for leaks it should easy see the wet fluid if the area is clean. Keep bleeding the rear passanger until no air comes out. Make sure the reservior stays full or air will be sucked into system during bleeding. Then you have to bleed again maybe this is what happed? If air is coming out the back aventually it will turn to fluid but there is not that much fluid in the system (4-6) quartz so it should not reqiure that much fluid. How much fluid did you bleed out of the system? How much fluid did you add to the system? I would recommend a complete flush. Fluid is cheap brake components are not.

sounds like a leak in the system. Clean the area (car wash pressure hose) then inspect all the brake lines in the system after pumping the brakes. the wetness should make it obvious. If no leak then continue bleeding. still no luck do the bench bleed again.

 

I bleed all brake again using motive power bleeder. That thing works great.

I just couldn't find proportioning valve on my 1996 4runner limited edition. The proportioning valve diagram in the manual is very simple and doesn't really show the location of it.

Anyone know where the proportioning valve for 96 4runner?

Thanks

 

I bleed all brake again using motive power bleeder. That thing works great.

I just couldn't find proportioning valve on my 1996 4runner limited edition. The proportioning valve diagram in the manual is very simple and doesn't really show the location of it.

Anyone know where the proportioning valve for 96 4runner?

Thanks

 

on my truck it sits right above the rear axle at little to the right. Careful because your truck may not have one. I think in 96 only the tacoma has that but I could be wrong. Hopefully some one will correct me if I am wrong. Yah that motive power bleeder rocks. Did you ever solve the air in the brake system problem?

 

The motive power bleeder should get all the air out, but my brake still soft like before. I am pretty sure there is no air in my brake system.

So the next thing I can think of is to bleed the proportioning valve which the service manual said I must do for replacing the Master Cylinder. So I must have one somewhere

The service manual shows a location of porportioning valve but I could match the diagram with any part of my 96 4runner.

I did find a brake unit above rear axel has brake lines goes to the two rear brake but I didn't see any bleeding valve.

 

Finally I took my car to Toyota dealer. After replacing rear wheel pads and wheel cylinders, they couldn't find leak and the soft pedal problem. Finally a toyota tech tested the new Master Cylinder I bought and it was defective.

So the Master Cylinder that I bought from Kragen auto part was defective and it was a rebuild unit also. It was only $95 compare to $209 Toyota OEM.

After replacing with Toyota Master Cylinder, my pedal feel fine now.

Thanks for your help and suggestions.

 

Everytime I used to use aftermarket Toy parts, it winds up costing me money and time. Everytime I use Toy parts, they fit and work like they oughta. I stick with Toy now.