4th Gen Mushy Brake Pedal

H

Halfsmoke89

New member
Hoping for some insight here.
I've been having issues w my brakes. I get mushy brake feel when gently or slowly coming to a stop. More aggressive stopping I still have pressure in the pedal.

When it's mushy I can pump and get pressure back.

I've bled the brakes myself a few times with no luck, and even took to dealer for a bleed after reading about the different procedures due to hydraulic assist and accumulator in threads on here, and maybe even need for the techstream.

I'm leaning towards internal seal issue w MC because of the symptoms.

Truck is 06 w 4.0 at 115k mileage.

Any input appreciated, thanks.
 
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Halfsmoke89 said:
Hoping for some insight here.
I've been having issues w my brakes. I get mushy brake feel when gently or slowly coming to a stop. More aggressive stopping I still have pressure in the pedal.

When it's mushy I can pump and get pressure back.

I've bled the brakes myself a few times with no luck, and even took to dealer for a bleed after reading about the different procedures due to hydraulic assist and accumulator in threads on here, and maybe even need for the techstream.

I'm leaning towards internal seal issue w MC because of the symptoms.

Truck is 06 w 4.0 at 115k mileage.

Any input appreciated, thanks.
Click to expand...
Mine was doing that, turned out to be the calipers up front. Take tires off, pry the pistons back and have someone step on the brakes a few times while you watch to see if everything is moving. The two inside pistons on both front calipers were froze up on mine. Replaced them, all good again.
 
t-man said:
Mine was doing that, turned out to be the calipers up front. Take tires off, pry the pistons back and have someone step on the brakes a few times while you watch to see if everything is moving. The two inside pistons on both front calipers were froze up on mine. Replaced them, all good again.
Click to expand...

Thanks. I've replaced both fronts already, within the past 3 months. Both were seized. Problem is still there. I'm confused though, because I felt it happen while driving 6 months ago and the problem hasn't gotten worse...
 
Halfsmoke89 said:
Thanks. I've replaced both fronts already, within the past 3 months. Both were seized. Problem is still there. I'm confused though, because I felt it happen while driving 6 months ago and the problem hasn't gotten worse...
Click to expand...

I've seen some guys saying they get frozen calipers every year or more often even, but if yours has been happening non stop I'm not sure, especially if you have bleed the brakes. Did you do the rear's too? [MENTION=66389]BlackWorksInc[/MENTION] might have some insight here too.
 
Its funny I was just about to search for this topic but noticed it on the first page!

I recently replaced my bearings at the garage and ever since getting the truck back, the brakes have been really mushy. I noticed on a hard stop, the vehicle would veer to left. It never did that before! Could it be a newly frozen caliper??
 
Theo85 said:
Its funny I was just about to search for this topic but noticed it on the first page!

I recently replaced my bearings at the garage and ever since getting the truck back, the brakes have been really mushy. I noticed on a hard stop, the vehicle would veer to left. It never did that before! Could it be a newly frozen caliper??
Click to expand...

Mine was pulling like that on hard stops too. I would pull the tire and check them. Mine were actually in the dangerous zone cause only one side was pushing on the rotor, bending the rotor in to touch the other side... Not good!
 
Theo85 said:
Its funny I was just about to search for this topic but noticed it on the first page!

I recently replaced my bearings at the garage and ever since getting the truck back, the brakes have been really mushy. I noticed on a hard stop, the vehicle would veer to left. It never did that before! Could it be a newly frozen caliper??
Click to expand...

Vehicle pushing to one side only during braking usually indicates a caliper that's not pulling its weight.
 
I've noticed during pedal testing while truck is off, pedal loses pressure almost completely after 3-5 pumps. When truck is on and in park I get 10 pumps before indicator lights come on. I never get more than 10-12 pumps before lights come on.

Not sure how to proceed next.
 
Halfsmoke89 said:
I've noticed during pedal testing while truck is off, pedal loses pressure almost completely after 3-5 pumps. When truck is on and in park I get 10 pumps before indicator lights come on. I never get more than 10-12 pumps before lights come on.

Not sure how to proceed next.
Click to expand...

It's supposed to do that. When key is off and you pump it 5 times it releases the pressure. Won't do it if key is on.
 
Halfsmoke89 said:
Hoping for some insight here.
I've been having issues w my brakes. I get mushy brake feel when gently or slowly coming to a stop. More aggressive stopping I still have pressure in the pedal.

When it's mushy I can pump and get pressure back.

I've bled the brakes myself a few times with no luck, and even took to dealer for a bleed after reading about the different procedures due to hydraulic assist and accumulator in threads on here, and maybe even need for the techstream.

I'm leaning towards internal seal issue w MC because of the symptoms.

Truck is 06 w 4.0 at 115k mileage.

Any input appreciated, thanks.
Click to expand...

OK, two things:
1) the 4th gen Runner is a ***** to properly bleed. You must go overkill! You have to bleed each valve until you can do TEN, yes TEN pumps with pure fluid.
2) if you are still having this issue post bleeding the way I stated above, then you need to have your master cylinder looked at. I'm sorry to say that IF it is your MC, you're going to have to shell out about $3k to replace it. I dread the day that I have to do this to my Runner.
 
Same issue on my 03 Turns out it was the hard lines replaced and it took care of most of it! They were not that expensive. I all so added stainless line that help for some of the pedal feel..
 
preacher35 said:
OK, two things:
1) the 4th gen Runner is a ***** to properly bleed. You must go overkill! You have to bleed each valve until you can do TEN, yes TEN pumps with pure fluid.
2) if you are still having this issue post bleeding the way I stated above, then you need to have your master cylinder looked at. I'm sorry to say that IF it is your MC, you're going to have to shell out about $3k to replace it. I dread the day that I have to do this to my Runner.
Click to expand...

Thanks. I've taken to dealer already for bleed and check since my bleeding didn't fix it. They bled and said everything was good, of course the pedal went to the floor while leaving the parking lot. Taking back for full diagram soon.
 
Dsimm said:
Same issue on my 03 Turns out it was the hard lines replaced and it took care of most of it! They were not that expensive. I all so added stainless line that help for some of the pedal feel..
Click to expand...

What was wrong with the hard lines? I haven't checked mine yet? Was it leaks?
 
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