Hydroboost keeps leaking - need ideas..

[Twisted1]

I’ve rebuilt a few hydroboosts (specially for 99-04 Mustangs) and always had a good outcome. As of this year, the company that I buy my rebuild kits from changed in quality, and I say that because the last 4 hydroboosts I’ve rebuilt have leaked within 300-400 miles. When I opened them back up, the “8” shaped o-ring had failed..

Are there any brands or kits you guys can recommend? I’ve even thought about using Toyota or even Honda Transmission gasket maker in place of the rubber o rings since ATF flows through the hydroboost system in Fords.

Thanks all.

 

[ElectroMechanoMan]

Pardon my ignorance but hydroboost is power brakes, correct? My confusion is that I’ve only seen or heard of ATF in a brake booster in diesel trucks because they have no vacuum. As far as the leaking seal is concerned, can you get a replacement from a dealer? I find myself getting absolutely fed up with aftermarket parts these days.

 

[Twisted1]

Pardon my ignorance but hydroboost is power brakes, correct? My confusion is that I’ve only seen or heard of ATF in a brake booster in diesel trucks because they have no vacuum. As far as the leaking seal is concerned, can you get a replacement from a dealer? I find myself getting absolutely fed up with aftermarket parts these days.

You’re correct. They’re typically found in diesels but since the 4.6 motor is a little wide the hydroboost fits better in these cars (Ford engineering)..

Unfortunately there are no OEM offerings for the gasket otherwise that would’ve been me first (and only) choice..

 

[ElectroMechanoMan]

I was a mechanic at an aftermarket Harley shop for a while. The rocker boxes on all Harleys use a rubber gasket that tends to harden from the heat so we would coat them with Permatex Anerobic Gasket Sealer. It does not harden and helps preserve the rubber. Hylomar gasket sealer may also help. This also may help preserve the rubber .

 

[D60]

Pardon my ignorance but hydroboost is power brakes, correct? My confusion is that I’ve only seen or heard of ATF in a brake booster in diesel trucks because they have no vacuum. As far as the leaking seal is concerned, can you get a replacement from a dealer? I find myself getting absolutely fed up with aftermarket parts these days.

GMT800 gassers got it, too. It was kinda sporadic but definitely not uncommon.

 

[Shannonwilkerson]

GMT800 gassers got it, too. It was kinda sporadic but definitely not uncommon.

Same with gmt400 gassers. My dad has a 1999 c3500 with the 5.7/4l80e and hydroboost

 

[dfarr67]

Sorry I don't have a name- but I did run in to a company that supplied rebuilders, had to order a min quantity. For such a simple unit never had much luck resealing- I buy new on fleabay now or used. My problem was the big o-ring always getting clipped. Elder Rubber Co

 

[4WD]

This was used as an example trying to sell me an extended warranty on a GMC - HB = mostly part - limited labor. Lockup torque converter pin is the other way around …
I yield the balance of my time to the gentleman up north @clinebarger

 

[andyd]

The ultimate fix is vacuum booster in a hydro-boost gasser. The go fast E 28s had hydro boost brakes. They all messed up and rebuilds were expensive. 99.9 % of scrapped 528es had the original vacuum set up

 

[4WD]

I was a mechanic at an aftermarket Harley shop for a while. The rocker boxes on all Harleys use a rubber gasket that tends to harden from the heat so we would coat them with Permatex Anerobic Gasket Sealer. It does not harden and helps preserve the rubber. Hylomar gasket sealer may also help. This also may help preserve the rubber .

Good point - extreme service equipment I work with does not go by miles and all that. The day it’s handed over with the CoC - clock starts ticking. Elastomers decay and flat spot even in storage …
Worse in use … Keep it “fresh” …

 

[clinebarger]

Prep the halves well with a sheet of fine sandpaper on a granite surface plate & apply some Anaerobic Flange Sealant outside the figure 8 O-ring & Let it cure 24 hours.

New GM units are still available & I'm not above disassembling one to repair/rebuild a discontinued/rebuilt only unit.

 

[Twisted1]

Prep the halves well with a sheet of fine sandpaper on a granite surface plate & apply some Anaerobic Flange Sealant outside the figure 8 O-ring & Let it cure 24 hours.

New GM units are still available & I'm not above disassembling one to repair/rebuild a discontinued/rebuilt only unit.

I wish there was an aftermarket offering for my application but there’s nothing good out there at all. Thanks for the tip about the granite surface plate =)

 

[BlakeB]

The hydroboost started leaking on my dad’s 2016 Duramax recently. I debated rebuilding it, but ultimately decided to replace it with a new Bosch unit from RA. The Bosch is 100% brand new and is the exact same thing (as far as I can tell) as the new GM HB at about half the cost. I did some research on rebuilding it and I found several places where people recommended this kit, claiming that other cheap kits had failed in short order and the made in USA kit that I linked had held up well. They also sell a seal installation tool as well, but it says for truck and SUV only. The seller has several hydroboost seal kits available so make sure the one I linked works for your application. If I decide to rebuild the HB I took off my dad’s truck, that’s where I’m gonna get seals from. Good luck with the repair or replacement, let us know how it goes.

 

[Twisted1]

The hydroboost started leaking on my dad’s 2016 Duramax recently. I debated rebuilding it, but ultimately decided to replace it with a new Bosch unit from RA. The Bosch is 100% brand new and is the exact same thing (as far as I can tell) as the new GM HB at about half the cost. I did some research on rebuilding it and I found several places where people recommended this kit, claiming that other cheap kits had failed in short order and the made in USA kit that I linked had held up well. They also sell a seal installation tool as well, but it says for truck and SUV only. The seller has several hydroboost seal kits available so make sure the one I linked works for your application. If I decide to rebuild the HB I took off my dad’s truck, that’s where I’m gonna get seals from. Good luck with the repair or replacement, let us know how it goes.

It’s funny that you linked that seller because I actually spoke to him throughout the day yesterday and he was beyond helpful. I have to resonate what others that you read had to say about him, which is he was very knowledgeable and stood behind his products. He said that his kits do not leak and the times they have, they were due to install error (which was why he developed the install tool). Thank you for the link as future BITOG’ers in my shoes will be able to find this now.