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Hi,
Kinda don't know what to think about this. I've a 2007 gx with 140,000 miles on it. A few weeks ago i noticed a sound under the dash kinda like a squeaky spring whenever I'd depress the brake. Thought it was just that. Then one rainy cold day I got in my truck and my foot went to the floor when i depressed the brake. No CEL or christmas lights like ABS, VSC etc. Although the brake pedal went almost to the floor the truck still had brakes, and still does. I've had to get used to not having a stiffer brake but the truck stops fine. No fluid loss and no pulling left or right. Kinda stumped. Accumulator? read its rare that goes. Booster motor? Read that goes around 200,000. When I press the pedal now I hear a faint chirp sound, like a little bird. Partial depression of brake is soft but the truck slows and stops w/o difficulty as I apply more pressure. Pedal does not hit floor. Looking at refurbished booster for 600 with install at 450. I haven't had it looked at yet but wanted thoughts. Vacuum leak? I dunno WTF.
Thanks for any thoughts or similar experiences
My first guess would be the check valve that keeps the booster full of vacuum.
Its most likely leaking down.
Thank you. Where would it be located? There is a line that runs from below the accumulator base to just under the reservoir where it affixes to a L-shaped plastic piece that seems to pressure fit into the unit. Not thinking that's it.
Thank you. Where would it be located? There is a line that runs from below the accumulator base to just under the reservoir where it affixes to a L-shaped plastic piece that seems to pressure fit into the unit. Not thinking that's it.
JeffLee
yes.... it’s going to be attached to the vacuum line running to the booster. In most cases. Let me pull it up on all data. I’ll show you an exploaded diagram.
So these systems are different than the usual brake boosters we see.
As as you can tell... there is an electric pump attached directly to the system... and a small accumulator screwed down on top.
Not exactly what I’m used to dealing with but it does simplify the system in an expensive way.
My guess would be that your accumulator(circled) isn’t holding vacuum under pressure.
Id take a look at the accumulator for any cracks. You can also remove it and replace the seals... which is most likely the problem.
Since you have brakes but tge pedal travels travels to far... that tells me that you have vacuum assist... just not any spare vacuum to help take a strain off the pump and help with braking.
If you you need more pics or direction... let me know. But I’m going off the fact that your hydraulics are in good shape since you said you had no leaks.
But make sure your brake fluid is staying full. Or even bleed the brakes at one caliper and see if you get your pedal travel back.. even if it’s temporary.
Thanks so much. Very helpful. It’s not lost any fluid. I have a similar brake system in my Saab 900 (‘93). The accumulator is shot and it stops in a similar way. When my truck still stopped i should have thought about my Saab’ s story. However, Toyota over engineers everything so I figured Id seek another opinion. Thanks again.
It’s the original Accumulator and probably not a bad time to replace it. I’ll start with an o-ring first 😊
Thanks MrJason. Please clear something up. Are you indicating the entire unit is failing or just the accumulator ( booster bulb)?
thank you
I can’t make that conclusion without actually looking at your car.
It could be either one. I’d check the integrity of the accumulator... if it appears in good shape... I’d rebuild the hydraulic pump.
But it first thing I’d check is for trouble codes in the system. You need a scanner that can read the abs module.
If the accumulator has has leaked down I would think a pressure sensor would see that.
Haven't attached a reader as of yet. Just commenting that nothing on the dash is popping up. taking my truck in this week to have front end aligned and will have them look at the brakes also.
Rygar is correct in asking about the type of scanner... you need one that will “scan” the modules.. not just a “code reader”.
As as long as it will communicate with the abs module it should work.
I also find find it hard to believe that the accumulator lost enough pressure to cause a soft pedal without lighting up your dash. It has a pressure sensor looking at the accumulator pressure.
04-03-19, 08:43 AM
Booster baffle
