2002 brake failure mater cylinder pump accumulator and motor assembly - Toyota 4Runner Forum

wrpsuite · 08-23-2019, 11:26 AM

Can find used assembly locally for $500 or $1100 new from dealer (with my mechanics discount) and not sure what to do? Risk a used faulty part or bite the bullet and put upwards of 20% of truck value into it.

Truck has 186k and I’d love to keep another 8-10 years. I cant tell you how many threads I’ve read the past few years trying to resolve the intermittent noise and vsc/check engine lights. Well master cylinder finally started leaking and with low fluid no brakes and constant warning beeping.

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nissanh · 08-23-2019, 12:31 PM

Have you tried to replace the seals inside the master pump? I have a Land Cruiser and those also got that expensive pump. Most Landcruisers get the pump accumulator symptoms at or above 250K miles. You have quite low miles.

Try replacing the washers and I think the OEM kit is like $50.

Here is the rebuild thread Master Cylinder Rebuild - DIY | IH8MUD Forum

Complete sudden brake failure | IH8MUD Forum

Sarki · 08-23-2019, 12:48 PM

If in fact you determine replacement is needed I would probably go for the new OEM unit vs. used unless you can confirm the used unit was from a low mileage Runner.
Definitely worth looking at rebuild kit before spending the big $$$ on used or new though.

rightyouareken · 08-24-2019, 12:29 AM

What symptoms are you having? I recently replaced my whole brake booster/master cylinder assembly with a new part to the tune of ~$2,000, but before I did that I did quite a bit of diagnostics.

Post up your in depth symptoms and what you've tried so far and I'll try to help. If it's just a master cylinder leaking, there is a rebuild kit available for about $50-75 from the dealer. Or you can replace the master cylinder/ABS valve body for about $1000.

The symptoms I was having was this loud screeching noise on each startup every morning, and usually after the first brake application as well. After that, it was quiet the rest of the day. The noise starts around 22 seconds in this video (not my car). My noise would last around 2-3 minutes every morning by the time I finally got fed up enough to replace it.

YouTube

There are several sub components that can be replaced individually, but you need to be sure what part is the problem first. In my case, the issue was traced fairly confidently to a bad high pressure switch. It seemed to not work properly when cold, causing the system to overpressure and cause that noise. Unfortunately that switch is integral to the ABS valve body and isn't an individually replaceable part.

wrpsuite · 08-24-2019, 07:38 AM

Quote:

Originally Posted by rightyouareken

What symptoms are you having? I recently replaced my whole brake booster/master cylinder assembly with a new part to the tune of ~$2,000, but before I did that I did quite a bit of diagnostics.

Post up your in depth symptoms and what you've tried so far and I'll try to help. If it's just a master cylinder leaking, there is a rebuild kit available for about $50-75 from the dealer. Or you can replace the master cylinder/ABS valve body for about $1000.

The symptoms I was having was this loud screeching noise on each startup every morning, and usually after the first brake application as well. After that, it was quiet the rest of the day. The noise starts around 22 seconds in this video (not my car). My noise would last around 2-3 minutes every morning by the time I finally got fed up enough to replace it.

YouTube

There are several sub components that can be replaced individually, but you need to be sure what part is the problem first. In my case, the issue was traced fairly confidently to a bad high pressure switch. It seemed to not work properly when cold, causing the system to overpressure and cause that noise. Unfortunately that switch is integral to the ABS valve body and isn't an individually replaceable part.

Thats the same noise I’ve been having for years especially when wet or cold. Sometimes an alarm would come on for a bit too. I’ve researched for a solution quite a bit but probably like you was told this combined system is prone to failure. I flushed the system and looked for parts to replace but now its seems inevitable.

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rightyouareken · 08-26-2019, 11:59 AM

Because you appear to have two issues (morning noise/alarm and leaking master cylinder) I think you have a few options:

First of all, here's what we're dealing with.

In this diagram, you can purchase the whole assembly or a few sub assemblies, or some individual parts.

#1 (part #47050-35010) is the entire master cylinder/ABS module + booster motor/pump/accumulator. Available new for ~$2100
#2 (part #47025-35010) is the master cylinder/ABS module (without the booster motor/pump/accumulator). Available new for ~$1200.
#12 (part #47070-60010) is the booster motor/pump/accumulator. Available new for ~$800.

You can probably find a used assembly (equivalent to #1 above) for ~$500 or maybe even less. The trouble is it might have the same issue as yours...there's no way to know until you install it.

You could also just rebuild the master cylinder piston with the overhaul kit from Toyota ($65, part #04493-35340) but that will only solve your master cylinder leak...not the morning noise/alarm.

You could buy a new master cylinder/ABS module assembly (#2 above) for ~$1200 and that should solve both your leak and the morning noise/alarm. If you want to go with new parts, but are budget constrained, that may be a good option, but you'll have to do some disassembly and transfer your booster motor/pump/accumulator over. Also, some people end up having one or more of those parts fail eventually too, at which point you'd have to replace those as well, costing more money.

Or you could just bit the bullet and replace the whole assembly with a new one, and probably be good to go for another ~15 years, 180k miles. That's the option I chose to go with because it essentially refreshed all of the components to new, and I have peace of mind knowing that I haven't introduced some failure point by taking the system appart.

Good luck with whichever way you chose to go!

gamefreakgc · 08-26-2019, 12:03 PM

They are a bit cheaper on Ebay, can be found for about $400.00. There's normally sellers with good return and refund policies and if you pay through PayPal, they have your back if your item is a lemon. You'll have 30 days to install and see if it works I think. That's what I would recommend.

wrpsuite · 08-27-2019, 07:32 PM

Quote:

Originally Posted by rightyouareken

Because you appear to have two issues (morning noise/alarm and leaking master cylinder) I think you have a few options:

First of all, here's what we're dealing with.

In this diagram, you can purchase the whole assembly or a few sub assemblies, or some individual parts.

#1 (part #47050-35010) is the entire master cylinder/ABS module + booster motor/pump/accumulator. Available new for ~$2100
#2 (part #47025-35010) is the master cylinder/ABS module (without the booster motor/pump/accumulator). Available new for ~$1200.
#12 (part #47070-60010) is the booster motor/pump/accumulator. Available new for ~$800.

You can probably find a used assembly (equivalent to #1 above) for ~$500 or maybe even less. The trouble is it might have the same issue as yours...there's no way to know until you install it.

You could also just rebuild the master cylinder piston with the overhaul kit from Toyota ($65, part #04493-35340) but that will only solve your master cylinder leak...not the morning noise/alarm.

You could buy a new master cylinder/ABS module assembly (#2 above) for ~$1200 and that should solve both your leak and the morning noise/alarm. If you want to go with new parts, but are budget constrained, that may be a good option, but you'll have to do some disassembly and transfer your booster motor/pump/accumulator over. Also, some people end up having one or more of those parts fail eventually too, at which point you'd have to replace those as well, costing more money.

Or you could just bit the bullet and replace the whole assembly with a new one, and probably be good to go for another ~15 years, 180k miles. That's the option I chose to go with because it essentially refreshed all of the components to new, and I have peace of mind knowing that I haven't introduced some failure point by taking the system appart.

Good luck with whichever way you chose to go!

I went for the whole assembly and got mechanics discount at the dealer. Foind a used one for $500 but it worried me. Maybe i can sell my used one for $500 lol. Tough pill to swallow but in the long run cheaper than a new vehicle I’d like less. Ill report back once installed hopefully by the end of the week. I need to deal with where the brake fluid leaked but other than that good to go. Also have some 2018 rims ill put some tires on and still be ahead of the game. Thanks for all the input.

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rightyouareken · 08-28-2019, 07:27 AM

Good luck! I know its a bitter pill but I rationalized it by telling myself a lot of people here spend way more than that putting lifts, tires, bumpers, etc on their rigs. Heres to many troublefree years ahead!

wrpsuite · 09-04-2019, 11:46 PM

Replaced part with new from dealer and besides finding a line leaking and making a new one I’m all set and feeling good. Changed A/F sensor also and got through emissions. Happy camper

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rightyouareken · 09-05-2019, 07:15 AM

Good to hear! Heres to many happy miles ahead hopefully!

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