yes
Poll on total brake failure in 100 series (3 Viewers)
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yes
It "may" be a sign accumulator is tired. I say this because I've noticed in low mileage 100 series or when I've R&R accumulator. The pedal only take 22 to 28 pump before its strokes become long. In old weak system, I'll get near 40 pumps. Also I've seen were seals that are old, the booster motor run time is on the long side (~40 seconds). This improves with new seal or warmed-up seals.
No, 253k ‘99
At this point @ 241,000 miles so far so good hoping it lasts forever. Will continue to perform preventative brake maintenance procedure.
Wondering if you had a reveal 2001LC. About a year ago I purchased brand new OEM toyota accumulator pump motor assembly after mine was making the seagull noise and loosing pressure. I took old assembly apart and the wear and damage to electric motor was obvious, felt comfortable thinking this was definitively it (pics on my build thread) had no issues for a year silent great feeling brakes. Recently in the cold I started hearing noises again this is a different noise. No seagulls, no motor noise, the best way I can describe is like air rushing out of a tight fitting stopping for about a second and continuing for a total of 20-30 seconds
The circumstances of reproducing the noise are always the same, cold morning 40 below and not warming the truck and get going. If I wait and warm it up, no noise.
I've paid close attention to the noise recently and I can hear the actual pump motor running quietly but still hear the rush air noise, this is independent noise to the pump motor but its definitively originating from the assembly.
If your thinking bleeding brakes... not it unfortunately.
Now if I ignore the "swoosh" sound and continue driving while the truck moves around then I get the alarm. Its almost like don't move, let me warm up or I'll start swooshing noises.
Now... the only thing that is not new is the brake sub assembly (booster module master cyl) looking at that I took the FSM and checked oems on all terminals based on the FSM troubleshooting and received no resistance from the pressure sensor.
Could the pressure sensor be the cause of that swoosh noise? its definitively not working. I heard this sensor cannot be replaced on its own so my only route is to buy the 1200 sub assembly.
This only ever happens in the cold, so the rubber seal idea you are chasing is what I'm also wondering about.
I've been reluctant to post what I suspect and working on now. I'd like to finish the next faze of my test.
But if your getting "swoosh" on cold morning before or during "warm up" of brakes. "Warm up" by use of brake (fiction heat) and starting engine (radiated heat). Then the alarms come on with use pre warm up and alarm goes off as it warms. Then I'm thinking seals.
Then we've a problem. I now see two seals we can not buy separately from Toyota. They only come with master assembly (master and ABS black box)
Cold does shrink all rubber seals as does age and use. Which we've seals from end to end in the brake system. These includes calipers. You may be hearing a pressure loss. I do not think it's an air sound. They system does not have air in it. It would have to be internal or you'd see leak and level of reservoir would drop. It could be your hearing something total unrelated also.
The pump motor, if running over 40 seconds and alarms coming on at times, pre warm up or just when very cold. Indicates seals if pressure switch check out as Okay.
But if your getting "swoosh" on cold morning before or during "warm up" of brakes. "Warm up" by use of brake (fiction heat) and starting engine (radiated heat). Then the alarms come on with use pre warm up and alarm goes off as it warms. Then I'm thinking seals.
Then we've a problem. I now see two seals we can not buy separately from Toyota. They only come with master assembly (master and ABS black box)
Cold does shrink all rubber seals as does age and use. Which we've seals from end to end in the brake system. These includes calipers. You may be hearing a pressure loss. I do not think it's an air sound. They system does not have air in it. It would have to be internal or you'd see leak and level of reservoir would drop. It could be your hearing something total unrelated also.
The pump motor, if running over 40 seconds and alarms coming on at times, pre warm up or just when very cold. Indicates seals if pressure switch check out as Okay.
Pump running perfectly reaching pressure at 35 seconds consistently (bought new last year). Confirmed no resistance at pressure and no pressure from the pressure sensor. So that's malfunctioning sporadically. The swoosh sound from loss of pressure makes sense, I'm absolutely sure it's coming from the master cylinder as pump humms quietly and building pressure 35 secs at same time.
So here is where it's going to suck for everyone..
. There is a national shortage of master cylinder assembly. Confirmed this by multiple sources. Whole assembly at 2400 is the only immediate option. For now I let the truck warm up no issues
PM if you like, with contact info. We can talk!
Yes, Failed at 170k
2003
Had to replace the whole assembly at a cost of 2500? I think it sucked.
2003
Had to replace the whole assembly at a cost of 2500? I think it sucked.
Took my truck to local shop to have the brakes replaced. Picked my truck up after work was done and it did fine until pulling into parking spot, at which point I felt strange/rough feedback from brake pedal as I came to stop, followed by some beeping/warning noise and also ABS light lit up. Called shop to report issues and after some argument (unreal), they agreed to look it over. Turned off, then on, things seemed normal again. I head back to the shop, which is 1 mile from where I was parked. About halfway, and after several successful but slow stops, the brakes gave out entirely after I had to hit them more suddenly and deeper press due to traffic. I was doing about 25-30 and luckily had enough space to progressively apply E-brake to stop, kept it in lower gears and used E-brake the rest of the .5 miles to shop. They looked it over and blamed a rear piston? Anyways, they said they "took care of it", gave me my money back, and the brakes have been fine ever since. They've been replaced multiple times with no issues. I saw this post though, and figured I should share. May or may not be related to vehicle issues, or shop/technician issues..
Or left a bleeder open or only snug. Had they tested booster run time, it would have then been discovered. Frankly I seems to be lone-wolf on running the booster run time test and replacing bleeder caps.
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Might be overthinking this but over the last week or two, I feel like the pump is getting louder than it was when I purchased the truck a year ago. Hoping someone on this thread can relieve my anxiety or tell me I need to replace it. I took a video tonight. See below. 2005 w 178k looks to be original. Bleed all the system about 4 months ago and refilled with Toyota brake fluid.
Thanks in Advance.
Thanks in Advance.
Each brake caliper on the back side of wheel has a bleeder. They need close inspecting. Any wetness even just a tiny little bit on threads not even dripping just not dry, needs investigating. All bleeders need good rubber caps on them. Pull cap and check for wetness under also.
Re test the run time. Read and follow direction on reservoir for topping. Than on first IG key ON time how long booster motor runs. Spec is 30-40 seconds. Over 40 sec indicates and issue. Most common issue is air in lines and or leak.
See the wetness on caliper around the bleeder. It was a weeper I could not stop weeping even after increasing torque from 9ft-lbf to ~12. So I replaced the bleeder with Toyota OEM bleeder which took care of it.
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This is great! Thank you!
I just wanted to share since the ABS issue can be a $$$$ repair . ( This is my 2nd time), first was a years ago on a 99 LC, This time it’s a 2004LX)
So my ABS unit went bad and I came across a post on Craigslist of someone selling rebuilt ABS units for the LC and LX.
Turns out the guy Alex rebuilds them for a few dealerships and junkyards here in Sacramento and he has been doing it for 7 years.
(916) 668- 9638
500 for the unit with core exchange. (700 for98-00)
250 for the install
Called him around noon and had it fixed same night.
Mine just failed. 139k on a 1999. The alarm sounded, and soon after I had no brakes. I was on the 101 freeway in Los Angeles but luckily was able to exit and pull into a 7-Eleven where I called a tow. Looking forward to no more screeching.
