Leaking brake accumulator (1 Viewer)

[2000 hundy]

Hello fellow mudders:

Question for you. I recently had the complete master cylinder brake unit replaced using genuine parts, but the brake booster from city racer. The Indy shop I used, reused the o-ring that connects the brake booster and accumulator. Failure of the old reused o-ring led to a leak in the connection between the accumulator and booster and subsequent tow back to the shop. The Indy tech then substituted the o-ring with one from an a/c parts kit. Now, a few weeks later, another leak develops (same spot) and another tow back to the shop. The tech thinks that something else is wrong because the o-ring fit and therefore something else may be malfunctioning.

I believe that while the o-ring appeared to fit, it was the wrong size and therefore not sealing properly (albeit it worked for a few weeks). My solution is to hit up the Toyota dealer when it opens to get the correct o-ring to see if that’s the culprit.

Has anyone else experienced this issue? Any suggestions or knowledge bombs to drop for my current issue?
Thanks and much appreciated to the group.

Hello fellow mudders:

Question for you. I recently had the complete master cylinder brake unit replaced using genuine parts, but the brake booster from city racer. The Indy shop I used, reused the o-ring that connects the brake booster and accumulator. Failure of the old reused o-ring led to a leak in the connection between the accumulator and booster and subsequent tow back to the shop. The Indy tech then substituted the o-ring with one from an a/c parts kit. Now, a few weeks later, another leak develops (same spot) and another tow back to the shop. The tech thinks that something else is wrong because the o-ring fit and therefore something else may be malfunctioning.

I believe that while the o-ring appeared to fit, it was the wrong size and therefore not sealing properly (albeit it worked for a few weeks). My solution is to hit up the Toyota dealer when it opens to get the correct o-ring to see if that’s the culprit.

Has anyone else experienced this issue? Any suggestions or knowledge bombs to drop for my current issue?
Thanks and much appreciated to the group.

BTW: I have a 2000 LC.

 

[abuck99]

Your tech is lazy and causing (and costing) you unnecessary repairs and potential damage to your new master. Never a good practice to re-use "non-reusable" items especially a 22 year old o-ring. Installing another O-ring that "looks close" err... not good.


2 min of searching for the correct O-ring revealed

Shown below as 47950F

 

[awesomeissquid]

While the new o-ring the tech selected may have fit, was it also the same thickness and material composition as the OEM one? I would be concerned the one used may not be rated for use with brake fluid. I would honestly only use the correct part for the o-ring and I would not consider anything else as a potential issue until that was corrected and the issue continued.

 

[kwon-offroad]

Thread hack. When the unit is removed from car is it assumed the accumulator has no pressure in it? Or is there a procedure to release pressure prior to removing from booster/motor?

 

[abuck99]

FSM instructs to pump the brake pedal 40x with ignition off before removal of master- imagine that relieves any pressure and drains the fluid

 

[hoser]

My City Racer pump failed recently (1/2021 install). It first appeared like it was leaking from the accumulator (and I was hoping it was) but it was leaking from the pump. City Racer responded, it was an issue with early pumps and they've made changes since. YMMV. I have not posted about it yet because I have not pinpointed the issue. I have since replaced the entire brake assembly with OE.

 

[2001LC]

If it is the seal between accumulator and pump. Use only the Toyota seal. Brake fluid will damage rubber not made for brake fluid. Which @abuck99 posted for you. Very easy replace.

 

[2000 hundy]

Thank you all mudders. It is what I suspected. Hopefully, the right part will finally fix this problem.

 

[okoverland]

If it is the seal between accumulator and pump. Use only the Toyota seal. Brake fluid will damage rubber not made for brake fluid. Which @abuck99 posted for you. Very easy replace.

How do you replace this o ring? Pull entire master cylinder I’m assuming? I replaced my accumulator and motor about 15k miles ago (max) and my accumulator is pouring brake fluid out this morning. Drove 300 miles yesterday and no issues this came out of nowhere. This is a new oem unit.

 

[okoverland]

Actually I was way off on my mileage. I replaced it 4k miles ago.

 

[okoverland]

More info: pulled out the accumulator and the o-ring is damaged from the factory. I’ve got a new o-ring ordered from local dealer. What a PITA for an $800 oem part.

 

[2001LC]

Darn! To bad you're not in Denver, as I've 3 of those O-rings in stock.

Very unusual for a NIB OEM booster assmy, to have damaged O-ring. Stranger it took so long to leak.

Tip: Lube O-ring with brake fluid, for installation. Torque to 36ft-lbf

 

[okoverland]

Darn! To bad you're not in Denver, as I've 3 of those O-rings in stock.

Very unusual for a NIB OEM booster assmy, to have damaged O-ring. Stranger it took so long to leak.

Tip: Lube O-ring with brake fluid, for installation. Torque to 36ft-lbf

Yea that would be great if I was closer!! Dealer should have it Tuesday or Wednesday so not terrible.

Thanks for the tip. Any suggestions on getting the right torque without the special tool?

 

[2001LC]

If you can find a wrench to fit. Then add wrench extender adapter. Add torque wrench to extender.

 

[wevo]

More info: pulled out the accumulator and the o-ring is damaged from the factory. I’ve got a new o-ring ordered from local dealer. What a PITA for an $800 oem part.

View attachment 3333647

View attachment 3333648

Did you have to remove the entire master cylinder to get the accumulator off?

 

[okoverland]

Did you have to remove the entire master cylinder to get the accumulator off?

No, I loosened the little bracket/stabilizer that surrounds it. Then used an oil filter removal tool (one of those with the rubber strap) to remove it. Unscrewed it and pulled straight up and out. Be careful there are small parts where it connects to the motor.

 

[wevo]

Ah, I was thinking that bracket was holding the pump/motor/accumulator assembly onto the master cylinder. I was going to stop in at O-Reilly's tomorrow and pick up a 2-5/8" 4-pin Toyota Lock Nut socket and modify it to work (similar to the 09318-12010 SST) but I've got one of those rubber strap wrenches so I'll try that first. I tried using my 8" adjustable spanner wrench but I didn't have enough leverage to break it loose.

 

[okoverland]

Ah, I was thinking that bracket was holding the pump/motor/accumulator assembly onto the master cylinder. I was going to stop in at O-Reilly's tomorrow and pick up a 2-5/8" 4-pin Toyota Lock Nut socket and modify it to work (similar to the 09318-12010 SST) but I've got one of those rubber strap wrenches so I'll try that first. I tried using my 8" adjustable spanner wrench but I didn't have enough leverage to break it loose.

Do you have a leak too or just replacing accumulator? The only issue I had was when replacing the accumulator I couldn't tell if I had the right torque. I never really looked for the SST but I see they are pretty high.

I wonder if this would work, I may try that.

Amazon product ASIN B000N37EEY

 

[wevo]

Do you have a leak too or just replacing accumulator? The only issue I had was when replacing the accumulator I couldn't tell if I had the right torque. I never really looked for the SST but I see they are pretty high.

I wonder if this would work, I may try that.

Amazon product ASIN B000N37EEY

I'm replacing the accumulator. That Performance Tool W1272 is the one I was going to pick up at O-Reilly's. It's 1/2 the price on Amazon but it wouldn't have gotten here by the time my parts came in. It'll work in place of the Toyota SST, which has 8 removeable roll pins where as the W1272 tool has 4 roll pins. I don't know if the roll pins are removable so you may have to cut 2 of them off to make it work with the accumulator.

 

[wevo]

Do you have a leak too or just replacing accumulator? The only issue I had was when replacing the accumulator I couldn't tell if I had the right torque. I never really looked for the SST but I see they are pretty high.

I wonder if this would work, I may try that.

Amazon product ASIN B000N37EEY

I ended up just buying the PT W1272 tool which made the job a breeze. The pins must be held in place with loctite because they came out fairly easily once I heated them up.