GM Hyroboost seal kit info

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dfarr67
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GM Hyroboost seal kit info

Post by dfarr67 »

I cannot find any info on these, generally GM hydroboost came is a couple piston sizes, looking for the main piston seal for a 2005 HD truck. Last kick at resealing before scrapping this spare unit- put a new GM unit on the truck and it is working.
GM 475998
GM 465226
Don't want to use any aftermarket seals here- been there done that...
Racer71
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Re: GM Hyroboost seal kit info

Post by Racer71 »

I’ve bought a few kits from I believe it was called southwest speed. They have partial and complete kits
dfarr67
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Re: GM Hyroboost seal kit info

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What's your luck in long term service- for such a simple unit I cannot make them work. I was advised to put a new year on and I picked up a 2021 GM OEM and it has differences.
Racer71
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Re: GM Hyroboost seal kit info

Post by Racer71 »

I’ve done two gmt-400 body trucks now and haven’t seen either one back yet. One had recently been done by someone else, owner wasn’t very forthcoming if he tried it or a buddy etc. the brake pedal rod is different on the newer ones I’ve done that retrofit as well. My sister shop is a body shop that only rebuilds late model wrecked Chevy trucks, so I’ve grabbed low mile leftover ones from parts truck and retrofitted
dfarr67
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Re: GM Hyroboost seal kit info

Post by dfarr67 »

I ended up purchasing both those NOS GM kits off of fleabay- I'm thinking my problem was poor quality seals.
For future reference- good reputation for north american manufacturer of seals- min order tho. http://www.elderrubber.com/thankyou/

Cdn co that rebuild units......
Edmonton Brake and Wheel= $485cdn
John Stuart= $285cdn

Ya- I admit I screwed the pooch on the takeout, I installed 2005 Suburban K1500 disc brakes all around on a 1989 K1500 and misrouted the front flex lines so that they pinched when let down off the jacks and it wasn't obvious. Thinking the malfunction was the the HB I literally tore into it and damaged the main seal while removing it- ruined a good unit and my spare leaked too. Sometime in that vintage they changed the rear of the MC to a larger diameter.
The mounting plate is easy to change, I made a threaded rod to adjust the brake pedal- it's in compression so I'm not worried that I dremeled a slot to let the crimp flex trying to remove the ball from socket.
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