Roger that - great advice! Thank you.....
I've owned this rig for about 8 months, this is my 2nd LC100
Brakes ...... Overdue write-up. (3 Viewers)
- Thread starter 2001LC
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I've owned this rig for about 8 months, this is my 2nd LC100
I had a mishap last week and needed to bleed the rear brakes, and now when I apply the brake pedal, I can hear a light clicking sound in and around the tranny shifter. As well, the booster motor will come on for about 2-3 seconds after about 4-5 pedal depressions while idling in park. Is this normal operation times for the booster? With the key off and pressure reduced, it takes about 34 seconds to reach max pressure and shut off, which I understand is normal, but I'm not sure about when the engine is running.
2001LC
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- #23
The brake booster motor comes on, to create pressure in the system by spinning the pump. This happens whenever brake system pressure drops, below a predetermined pressure.
Pressure drops because:
Pressure drops because:
- Use of brakes
- Over time, it bleeds itself off.
- Due to a leak. (We do not want this)
2001LC
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This post, is just to point to post #3 & 4 in this thread. Where I added more info:
With respect to issues:
With not flushing properly
A Toyota TSB which indicates all DOT III brake fluids are not the same.
The importance of good brake bleeder rubber cap.
With respect to issues:
With not flushing properly
A Toyota TSB which indicates all DOT III brake fluids are not the same.
The importance of good brake bleeder rubber cap.
Last edited:
Are you recommending to use Toyota brake fluid vs like Preston Dot 3 or 4 from Auto Zone. I am planning to flush all my 3 cars soon - 99LC, 2000 LC and 96 Avalon.
Not all DOT3 fluids are equivalent - there’s various add packages depending on, price, requirements, etc. Prestone would be the cheapest (junk) you can use.
Toyota DOT3 is its own special blend- I read a comparison a few years ago and Toyota fluid tested differently. Compared to other fluids in its class, it maintains its chemical properties longer, which translates to more heat cycles before it begins to break down, and slower absorption of moisture. Anecdotally, my digital brake fluid tester has settings for several different DOT grades, along with 4 different DOT 3 options- Toyota having its own setting.
I’m sure I’m the stuff we buy at the dealership is blended in the US, but to a different spec. And to add to what Paul said, hardly any Toyota dealerships are using toyota fluid to flush brake systems.
If you want it done right- learn to do it yourself.
Toyota DOT3 is its own special blend- I read a comparison a few years ago and Toyota fluid tested differently. Compared to other fluids in its class, it maintains its chemical properties longer, which translates to more heat cycles before it begins to break down, and slower absorption of moisture. Anecdotally, my digital brake fluid tester has settings for several different DOT grades, along with 4 different DOT 3 options- Toyota having its own setting.
I’m sure I’m the stuff we buy at the dealership is blended in the US, but to a different spec. And to add to what Paul said, hardly any Toyota dealerships are using toyota fluid to flush brake systems.
If you want it done right- learn to do it yourself.
2001LC
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I updated post #2 with some pictures of internal master seals. I've never posted these nor seen anywhere before today. These are the seals, which any rebuilt master would need replaced. But to my knowlege, no one has. Which makes claims of a rebuilt master false IMHO, if not replaced.
Did you have to fab a custom tool to remove the plug for the inner seals?
Besides the one that appears to be a square cut o-ring, the others look like typical EPDM o-rings. Surely someone could put together a rebuild kit for one of these.
Besides the one that appears to be a square cut o-ring, the others look like typical EPDM o-rings. Surely someone could put together a rebuild kit for one of these.
How many (12 oz.) bottles of Toyota brake fluid is required to complete a proper brake flushing?
2001LC
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- #32
No, not for this tear down.
The manufacture locks in the thread end, by hits to the housing bending metal inward. I ground down the housing, not caring if damaging this one.
A way to unlock and relock, would need to be developed, first.
A few parts that may be harder to find than the O-rings.
Thank you so much for this thread. i do have a question about the brake booster accumulator (pressure reservoir). I can hardly find any info on he life of this item and while many people know to change ou the booster pump, if your accumulator isn't holdin the charge that is also causing your booster to spin up more often causing the wear, right?
Any advice on the lifetime of this part and service interval? TIA.
Any advice on the lifetime of this part and service interval? TIA.
Thanks for the post. It’s very helpful. Quick question on run time. I’ve timed it from first start and by pumping it 40 times and I run in the mid 30s. It stops and restarts twice for a second during the run though. Is that normal or is it an issue that it’s not continually running?
2001LC
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I can't say much about accumulator, as I've yet to see it as a failure point nor have I put any study into them. That said, I'd assume they would take more fluid to charge (fill). Which would result in longer run time depending on if fully discharged. But not necessarily more often. Brake pedal stroke may also be longer and produce less brake assist.
I can say, it's best to replace booster assembly (motor, pump, accumulator, control wire) with new OEM. All at once!
Very best: Replace the whole deal (booster assembly with master). Is the sweet spot cost wise, reduces labor and is best insurance of long-term reliability.
Bottom line. One can just keep replacing parts as they fail. But long term, this results in higher parts cost, more labor and less reliability.
Yes, even new will pause 2 or 3 times.
Thank you. I may have missed it but didn't see the pauses being mentioned so it's great to hear that's normal. I just got my first 100 series (03 LX) last week and the brake flush is the first thing on the agenda. The PO couldn't remember when it was done last and the level was over the max line after pumping it 40 times so that's doesn't fill me with confidence.
I'm just going to bite the bullet and get it done at the dealership. I've done some brake work including bleeding the past but don't want to risk damaging the booster right out of the gate. Would suggest having them do a pressure test or anything else while I'm feeling spendy?
I'm seeing this for sure. The first 2 just told me "Dot 3" and didn't use the Toyota stuff. I wanted to go to a dealership because I thought it would better since they have the handheld or tech stream to the bleed them.
I don't have a lot of trust left in me so I would worried they would just put the cheap stuff in regardless. Maybe I should go to an independent shop and just bring my own fluid. I'm still a little hesitant to do it myself.
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