All new brakes w/ Tundra fronts, pedal is still spongy

[MonsterMaxx]

So I did all new brakes in wifey's '97 4runner.

Tundra fronts and all new rears.

New master.

Well bled, rear adjusters taken up, no bubbles coming up.

But the pedal is still going 3/4s of the way to the floor before it does much, just like it was before w/o the worn out system.

I did bed them in w/ 5 hard stops, it stops well. I did slam the brakes in the gravel and ABS is cycling.

I'm stumped. What am I missing??? Do I need to do something special with ABS to get it completely bled?

 

[nc-grayson]

Hate to beat a dead horse, but I, along with others, are probably going to recommend bleeding again. And again. And again.

 

[aykalper]

I'm going to suggest this: if you bled it that many times, you're probably good. I'd suggest finding a compatible bigger master cylinder...something that flows more fluid.

 

[MonsterMaxx]

I was like this before I did all the upgrades/replacements. I bled the heck out of it when we got it and figured it was just that the master needed replacement.

Now that's replaced and everything else, IDK what the issue is. Pretty sure that after 4 laps around the truck and no bubbles on the last lap I got all the air out.

Jacked the rear end up and adjusted the spanners until the rear brake started dragging on both sides.

Im stumped unless it's something in the abs that requires a computer to reset.

 

[thecole1098]

You probably did, but I guess it's better to ask anyways. Did you bench bleed the new MC before you installed it and bled at the wheel cylinders?

 

[MonsterMaxx]

by 'bench bleed' ???

I left the lines off, had my buddy slowly pressing the pedal while I held my fingers over the ports. The rear one picked up right away but I had to blow into the reservoir to get the front one pumping. 1 cycle of that got it pumping. Both were pumping fluid before connecting the lines.

 

[LittleCaesar]

Try bleeding with the engine running.....

 

[aykalper]

Try bleeding with the engine running.....

I've always thought this would make a difference but never have done it. Is the benefit just having the extra oomph from the booster? Would it really make a difference?

 

[LittleCaesar]

I've always thought this would make a difference but never have done it. Is the benefit just having the extra oomph from the booster? Would it really make a difference?

On older GMs and Fords it does in my experience. My guess is, without any hard data, is that the ABS needs to be on to be functional. A friend bled a Nissan with KOEO, and it worked well. On the GF's X5 it takes rather costly proprietary software to bleed the modular, it just won't happen in a driveway.
No changing her brake pads.

 

[mtbtim]

Did you start bleeding with the right rear, then left rear, then right front and finally left front? Does your rig have an LSPV (Load Sensing Proportioning Valve). If so, you bleed that last. For the rear brake adjustment, did you get the final adjustemnt by pulling the E-brake over and over again? When the rear brakes are properly adjusted, you should get 7-9 clicks when applying the E-brake.

Here's a couple videos that might help.
https://youtu.be/rnyK3V-OGn4

https://youtu.be/IJkVEBYSecs

 

[19963.4lsr5]

Did you do the pump pedal and bleed or open bleeder- push pedal to floor - close bleeder- release pedal and repete?


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[MonsterMaxx]

Did you do the pump pedal and bleed or open bleeder- push pedal to floor - close bleeder- release pedal and repete?


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y e s

 

[MonsterMaxx]

Did you start bleeding with the right rear, then left rear, then right front and finally left front? Does your rig have an LSPV (Load Sensing Proportioning Valve). If so, you bleed that last. For the rear brake adjustment, did you get the final adjustemnt by pulling the E-brake over and over again? When the rear brakes are properly adjusted, you should get 7-9 clicks when applying the E-brake.

Here's a couple videos that might help.
https://youtu.be/rnyK3V-OGn4

https://youtu.be/IJkVEBYSecs

Yes. Did the ebrake, it wasn't enough, so I jacked the truck up and adjusted the drums until I could hear the brakes dragging.

 

[MonsterMaxx]

Try bleeding with the engine running.....

ok, will try that...

 

[mtbtim]

It seems pretty obvious that you still haven't found the culprit for your brake issue. Maybe it's your brake booster. Maybe it could be a brake fluid delivery issue. The inside of rubber brake lines can collapse and cause a partial or complete blockage.

I don't think bleeding the brakes over and over again is going to fix this issue. It's something you haven't addressed yet. Does anyone know how to verify a brake booster is working right? As for the rubber brake lines, you have the two for the front calipers and two that go to the rear end. It's more money for you but maybe replace those rubber lines with some steel braided lines to rule them out as the problem. It's not really money wasted because braided lines are a nice upgrade.

Good luck!

 

[MonsterMaxx]

I replaced the rear one with braided line when we did the suspension lift.
I replaced the front ones yesterday with Stop Tech braided line.

The stock ones were really looking bad too.

The booster seems to be working fine and I highly doubt it would be the cause of a mushy pedal.

 

[Cree]

Two options: keep bleeding or take it in for a power bleed.

 

[19963.4lsr5]

Two options: keep bleeding or take it in for a power bleed.

Or buy your own power bleeder I love mine. You can make one too but you'll have to go junking and get a assortment of caps.

If you did the latter method I mentioned above I'll say run another qt through it bleeding. I know know a few times if I stopped as soon as the lines were clear of bubbles. I'd drive it not happy and rebleed and get more air out.


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[MonsterMaxx]

I rebled with it running and a tiny bit of air came out of the RF caliper. It was on the first pump though so I doubt it was trapped anywhere but in the caliper and I just missed it the first 4 times.

It's not perfect IMHO, but is a LOT better. Wifey is out driving it now...I feel better at least knowing that there ARE brakes.

 

[Cree]

Or buy your own power bleeder I love mine. You can make one too but you'll have to go junking and get a assortment of caps.

If you did the latter method I mentioned above I'll say run another qt through it bleeding. I know know a few times if I stopped as soon as the lines were clear of bubbles. I'd drive it not happy and rebleed and get more air out.


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I don't do brakes enough to justify a purchase. 70 bucks does a full flush/bleed at Midas. Id' bet most of his air is still down in the ABS module. Reason's I clamp lines and bench bleed when replacing components.