GM Hydroboost leaking, need to buy some time.

[Dborch41]

My son has a 2007 Suburban that, big surprise, has a leaky hydroboost module. I'm still debating on how I want to tackle the repair but what is certain is that it will have to wait at least another month. I live in the Tropics of Texas and summer here lasts a loooong time, and I'm at the age where I just can't handle the heat like I used to. It's not gushing fluid but he needs to top the pump off quite frequently. What I want to do is go against everything I believe in and put in a seal conditioner to maybe slow the leak a bit until I can do a proper repair.

What I'd like to know is what would be the best "mechanic-in-a-can" to do this nefarious (but necessary) deed? Again I'm not after a permanent fix, I just need to buy a little time until the heat is a little less brutal. Thanks in advance as always.

 

[Sequoiasoon]

I haven't tried it but many recommend AT-205.

 

[anderson]

amen to at-205. im against most snake oil but that stuff does work from time to time

 

[Dborch41]

I haven't tried it but many recommend AT-205.

Wow, a bit pricey but there's no point in going cheap if it doesn't work.

I'll probably give this a try. I'll break tradition and read the directions, the only info I could find on fluid capacity is "at least 4 quarts" so 1/2 a bottle should do the trick.

Thank you for the advice!

 

[meep]

At-205 in BRAKES??? Is this hydro boost for brakes? The leak is not on the brake fluid side, right?

 

[Chris142]

I would try a ps fluid with stop leak already in it. Don't expect it to work.

 

[Dborch41]

At-205 in BRAKES??? Is this hydro boost for brakes? The leak is not on the brake fluid side, right?

Nope, this won't go in the brake fluid reservoir. The hydroboost system uses power steering fluid pressure instead of engine vacuum to "power" the brakes, and that is what is leaking. The module itself goes in between the master cylinder and the firewall.
A brake fluid leak means the car stays in the driveway until it is properly fixed.

 

[meep]

.

Nope, this won't go in the brake fluid reservoir. The hydroboost system uses power steering fluid pressure instead of engine vacuum to "power" the brakes, and that is what is leaking. The module itself goes in between the master cylinder and the firewall.
A brake fluid leak means the car stays in the driveway until it is properly fixed.

Ahhhhh yes makes sense.

I would personally avoid it if everything else is working well. While I am not a chemist, my fear would be that it would soften rubber seals in the rest of the PS system. I have no idea if that would realistically shorten the life of anything at all. If you wanted to try, I might use a “less is more” approach and start with partial, fractional doses.

 

[JavierH19]

Bars leak works in ps systems but i'd only use an ounce and drive for a while to not overdo it. I used this supertech psf in my original 342k pump and it stopped my slow drip. It only seeps now.

https://www.walmart.com/ip/Super-Te...wl13=5091&selectedSellerId=0&wmlspartner=wlpa

 

[slacktide_bitog]

Besides AT-205 like already mentioned, there's also Blue Devil, and of course, Power Steering Honey

 

[Dborch41]

But wait, there's more...

Got a good look first hand at the issue in question, it turns out that the leak seems to be primarily coming from the round silver plug in the picture. I was considering doing a rebuild with new seals but most of the kits I've looked at don't include one for that little plug. What I'd really like to know is if I can remove the plug in situ to replace the o-ring without having to remove the entire booster assembly. That would really save a lot of hassle.

There are two small grooves machined into the plug as if it could be removed with a large flat-blade screwdriver, but obviously I'm totally unfamiliar with this installation. I'll do a deep dive for information on how this thing is put together, maybe I'll get lucky.

EDIT: The picture is rotated 90 degrees clockwise, I couldn't get it to upload otherwise.

 

[Egg_Head]

+1 for Blue Devil. Worked for in in my K-5 PS pump.

 

[50yr Street Mech]

A little AT-205, not the whole bottle. If you need more , add more. Usually seals in a day or two. Keep an eye on it. Keep the bottle in the truck with some power steering fluid and you're son can check it on his own, and add as needed

 

[meep]

But wait, there's more...

Got a good look first hand at the issue in question, it turns out that the leak seems to be primarily coming from the round silver plug in the picture. I was considering doing a rebuild with new seals but most of the kits I've looked at don't include one for that little plug. What I'd really like to know is if I can remove the plug in situ to replace the o-ring without having to remove the entire booster assembly. That would really save a lot of hassle.

There are two small grooves machined into the plug as if it could be removed with a large flat-blade screwdriver, but obviously I'm totally unfamiliar with this installation. I'll do a deep dive for information on how this thing is put together, maybe I'll get lucky.

EDIT: The picture is rotated 90 degrees clockwise, I couldn't get it to upload otherwise.

View attachment 302385

That plug may very well be an access for the pressure relief spring/ball. You are right, theres a good chance it’s just an o-ring in there.

 

[maraakate]

Probably an o-ring. You might be able to get by with one out of a cheap o-ring kit. If not what you can do (and please fix this ASAP) is put a THIN smear of Hondabond/Yamabond/Threebond around the o-ring and put it back together. Make sure all surfaces are clean and free of oil before you do so. I cannot stress THIN enough. And DO NOT use RTV. Only the stuff they use for sealing crankcases. This can be used if you disturb and o-ring and are unable to replace it. Usually works but could fail at any time so do not trust it.

Hack move for sure, but sometimes you have no choice...

 

[dfarr67]

As simple as the HB are- I never had any luck rebuilding them- maybe it's the quality of the kits, don't know. I end grabing something off fleabay NOS.

 

[Dborch41]

As simple as the HB are- I never had any luck rebuilding them- maybe it's the quality of the kits, don't know. I end grabing something off fleabay NOS.

A brand new one from Bosch is about $250 shipped from RA. Since the engine just got a major refresh and he really likes that truck, I think it's a worthy investment.
I couldn't help but notice that the superseding part no longer has that little plug, possibly a known weak point.

 

[dfarr67]

A brand new one from Bosch is about $250 shipped from RA. Since the engine just got a major refresh and he really likes that truck, I think it's a worthy investment.
I couldn't help but notice that the superseding part no longer has that little plug, possibly a known weak point.

I think every number of years they redo the design.

 

[crashz]

Hate to be this guy, but with those miles, maybe consider replacing the master cylinder at the same time? You know, while you're in there

 

[Dborch41]

Hate to be this guy, but with those miles, maybe consider replacing the master cylinder at the same time? You know, while you're in there

Oh you are 100% correct, I'll at least do a flush for now.

The truck originally belonged to his father in law and it was supposedly well cared for. I wish I had the time to go over it myself with a fine-tooth comb but it appears to be in pretty good shape.