Hey yall,

I recently had and issue with the vsc trac and associated warning lights coming on. The result is that I ended up at the dealership getting it diagnosed...the end result was a frozen brake booster or "hyrdoboost".


Has anyone replaced one on an 04 v8 before? Pictures? Tips? Place to buy the assembly?

Thank you,
Shane

Toyota Auto Parts at Toyota Parts East | Genuine OEM Toyota Parts

has links to master cylinder and or individual master cylinder componants

TOYOTA Parts

another supplier. Cost seem similar.

I recommend picking up a haynes manual from a local autoparts store or online, for the truck you own to give you step by step instructions of removal and installation of master cylinder. Great tips and tricks to get it done right on your own.

Does anyone have any experience with the return and rebuild offer through Rock Auto and Cardone? This is a tempting option for the price.

I know you mentioned you could buy the individual components in an earlier thread, still slightly skeptical but its very nice that there is the option there.


My only concern is that without a proper method to diagnose the unit you aren't sure what you will need to replace. (I mean if the accumulator pump is obviously bad its bad, but what about subtle problems?) TIS was useless in providing me with a procedure to test these units other than replace them completely. If anyone has any tips or tricks I'd be very interested in hearing testing methods?

go pick up a Haynes manual and learn what Toyota won't teach you lol no offense but as a toyota service tech shouldn't we be asking you these
questions

That is rude. There are various specialties and honestly, some parts are not fixable.. they must be replaced.

......

Actually he has a point, factory repairs often are replace entire assemblies more than individual parts. You can't even buy seperate components for the Hydraboost system from your parts counter at the dealership. I ran into this working on another hydraboost problem (my own actually) that I detailed some in another thread.

I had my service writer write my truck up as an internal repair order so I could file a TAS (Toyota Assistace Services) and get some factory support on the matter. After a few days they called me up and I talked to them and they explained to me that they see these units fail occasionally and just outright replace the entire unit. Me being the curious fellow I am and always wanting to learn more pressed for details about failures and diagnostic testing methods. Their response was, "Well if you've ruled everything else in the brake system out, then the unit is bad and replace it."

That's the approved factory method for determining if the hydraboost unit needs to be replaced... eliminate everything else. No pressure tests, no electircal testing, not even a scantool self check; just replace the unit if everything else checks out.

Now here's where it gets odd... You look up the service manual in the TIS (Toyota Information System) and guess what you find under Brakes? An entire section devoted to tear down and rebuild of the Hydraboost Unit. Has diagrams, step by step instructions to tear the thing down to every last nut and bolt and put it back together. BUT, not one damn sentence on how to actually diagnose a bad unit and if it needs to be rebuilt.

Thanks for being understanding of my comment. I didnt intend to pass off any offense in the matter. I'm really more on his thought process, if anyone should have the information to repair and diagnose key components in our trucks it should he a toyota service tech. I certainly recognize your motivation to learn and dig into whats needed in order to get the job done right. It used to be when you walked into a dealership you were mostly garuanteed that a master technition would be available to diagnose your vehicle's issues to a T. Now it seems they run a few computer tests and any components that come up with a malfunction just get replaced not repaired (in most cases). This makes dealerships look more like part swapers and less like tech service repair shops. just IMO

The hydraboost should be here today. Any tips on replacing the assembly? I ended up finding one from a salvage yard for $480 which isn't bad compared to the $3000 the dealership quoted.

Installation will be similar to a regular master cylinder, with extra wires and lines of course. The only problem I see you running into is going to be bleeding the system effectively. You can't just bench bleed these units like old school master cylinders, you have to use the scan tool to actuate the individual solenoids once installed.

That being said, the repair manual should outline removal and reinstallation. (a have links for online repair manuals I think, I could be wrong.)

Can you please provide the links to said manuals?

The websites I was referring to 4 years ago were shut down a while back. I think you can pay like 20~ish dollars for access to TIS