Hydroboost Unit Concern

[Mike07SE]

I think I already know the answer, but I'm looking for feedback...

My truck is 12 years young with 150K on the clock (probably realistically 10 - 20K more than that with the 33's it's run most of it's life).

I've been starting to notice that when the HBB kicks in at night with my lights on that it's beginning to draw on the system as I see a momentary dim coinciding with the pump motor running. Otherwise it seems fine as the pump kicks in only after about 5 applications of the brake pedal.

So I've been researching my options if this is something brewing as a failure.

1. Replace the pump motor. This option alone is about $450 from a rebuilder. Plenty of YouTube videos on this and seems fairly straight forward even with dismounting the whole unit.

2. Replace the pump and accumulator. I've found items available separately. It would seem like a good idea to do both while it's on the bench.

3. Replace the pump assembly as a whole - Pump Assembly - Toyota (47070-60050) - (2003-2019 Toyota Pump Assembly 47070-60050 | Conicelli Toyota of Conshohock). This seems like a cost effective option at ~$700 which I don't get as the pump ($1100) and accumulator (~$300) are about double the price than the assembly (am I missing something???). New pump, accumulator, and all incidentals included such as o-rings and gaskets (I assume?) that are Toyota Genuine seems to be the way to go. I'm assuming that replacing the Pump Assembly is about as easy as replacing the motor alone is. Any insight that anybody can provide on this? [MENTION=66389]BlackWorksInc[/MENTION] do you have any hands on experience to this?

4. Last option would be the whole unit itself, but I don't see the value in that if the control module and Master cylinder are fine.

 

[earthrealm]

your brake master cylinder is still working great, kicking in every 5th brake application, mine kicks in every time i depress the brake pedal!.. and then prediodically while am driving, thus i obviously have a leak in the system,

in your case, i feel the electric motor in the pump is getting worn out/dirty, opening up the motor and cleaning it up sounds like a good ist option. dropping in a remanned motor, a 2nd option.

should you still want to go ahead and replace the complete brake assy, with this
2005-2009 TOYOTA 4RUNNER ABS Brake Pump Master Cylinder 89541-35051 | eBay

i am willing to buy yours

 

[Mike07SE]

You may be right that it's still pretty much OK and just a wearing out motor. However from a point of preventative maintenance, I may go with option three and replace the Pump Assembly as that addresses the main wear / fail components.

 

[BlackWorksInc]

You may be right that it's still pretty much OK and just a wearing out motor. However from a point of preventative maintenance, I may go with option three and replace the Pump Assembly as that addresses the main wear / fail components.

That's probably the best way to go. I had mine actually have an atypical failure mode in that the actual hydraulic master cylinder portion (not the accumulator or motor) was having some oddball intermittent leakage past one of the internal seals. Every now and then it'd feel like the pedal wasn't doing too much and you'd double pump it and get good pressure. I don't see too many master cylinders go bad anymore, but they still can happen (I think the last one I replaced was a '93 Land Cruiser.)

It sounds similar to what you're experiencing. Sorry for the delay.