Good find Neal, thanks for posting that, I'm gonna follow up on these Monday, No Doubt Sweeting is making a killing on the complete assembly, I do wish I know how much luck people have had trying the master cylinder only and just trying to install that part and have it work properly?

 

Even though currently I am ok with only an occasional drip through the firewall but I know what might could be coming. Usually with the old Hydroboost this signifies the beginning of the end for those units.
So, what the hell I said screw it and just now ordered the replacement master cylinder part (2586147 only from GM Parts Giant) $632.43.

I have been on back order for the complete assembly (19258789) since the beginning of this year when I first noticed a drip of brake fluid on the pedal rod. No lights or brake problems at this point and the truck is fine, BUT we all know about Murphy's law.

If the complete assembly ever gets shipped (which I doubt at this point) I will put add it to my hard to find H2 parts bin (with the other thousands of dollars of parts I already have on hand) You can all see I am serious about keeping my H2.

At this point I'm all in, I am not going to gamble a few thou on having a vehicle I could never drive again or even worse have to junk because of a stupid brake part.

I really do hope someone here with superior knowledge can come up with a way to use the pre-08 Hydroboost unit on the 08/09 and still have everything work as it should. I don't think retrofitting the pre-08 hydroboost and master would be a problem, getting the ABS working correctly and getting all of the hooks out of the BCM software will be the issue. Gives me a headache just thinking about it. How's that for a challenge!

Cheers all,and kudos to Neal!

 

Thinking I may send Sweeting a message to see if they may have or know of a source for rebuild options for the master.

I also want to send a message to FiveR and see what they offer

Neal

 

Was researching their site and ran across this, a conversion from electric to regular hydro-boost for the 08/09 setup

https://www.powerbrakeservice.net/sw...-electric.html

Need to call them and see what info they will share,

Neal

 

WOW, that could be a game changer if it works, It does make me wonder what they would be using for a Master Cylinder considering this is what they have to work with now?

 

You could not retrofit an 03-07 system in an h2, but there are plenty of other 08-09 gmt900 trucks that came with hydroboost and an abs pump. If you could find a system from those trucks, it would 100% work. Just have to figure out programming and wiring, but it will work.

Btw I bought the last booster assembly off rock auto a year ago. Sorry guys.

Also that hydroboost conversion from Sweeting just covers the mechanical side. Their listing says nothing about the electrical side, and it deletes the abs and just uses a proportioning valve.

 

Gavin, as always your quick on the draw, smart you did that, The early bird gets the worm!

I had that on my list of things to buy but forgot about it. I had ordered just the master from GMPartsGiant back the end of last month but have yet to get a shipping confirmation. I had a similar thing happen for the complete assembly from GMPartsDirect back earlier in the year. After about 3 weeks they refunded me and said it was a computer stock error and that they didn't actually have one.

I do hope GMPartsGiant doesn't do the same thing to me. Ah the beauties of owning a limited production vehicle that's coming up on 20 years old. At least the pre-08 guys don't have to worry ACDelco still manufactures the Hydroboost units for them plus a ton of aftermarket companies as well, they will never have this issue.

Unfortunately the old Silverado 2500/3500's used the Hydroboost system used in the Pre-08 so there won't be any help there as far as I can tell the one in our 08/09 H2's were not used in anything else and the variants used H3 s are not even close. Toyota also used it in some of their 4WD vehicles again not even close.

So it's not looking good. If worse come to worse and since the electronics are good I will pull the master of the assembly, put it in my lathe, bore it and then make a new custom piston out of billet aluminum. Biggest challange might be getting the correct size and material O Rings for it not something I am looking forward to. I guess that $2500 Sweeting unit is looking better and better all the time even at their gouging price if GMPartsGiants falls through.

 

the plunger rod inside the master cylinder uses more of a flared seal not orings

 

Ouch, well, so much for my idea, finding flared seals in the correct materials and custom size will be about as easy as finding a complete booster unit, Oh Well, back to the drawing board.

 

Well folks you can forget GMPartsGiant and add them to the we sell what we don't have list. I ordered the master cylinder from them back on Aug 31, they charged my credit card then after calling for shipping status a number of time they cancelled the order (no email BTW) and according to a conversation this morning will credit back may card within 7 days, I also scolded them for charging my card before even verifying they had the part. **** poor to say the least.

Talk about crappy service and zero customer focus. This is the same thing that happened with another one of the GM parts house's earlier this year.

For what ever its worth if you try to order one of these parts make sure you get a human on the phone and have them physically verify they are in possession of the part, otherwise you will probably in up in the same boat. Oh well the search continues.