Dealing with power steering leak from brake booster

[mayvillain]

First post; I just graduated from the GMT400 forum when I bought a 2002 Silverado 2500HD. It has the 8.1L/Allison trans combo.

I bought it with a significant "power steering leak." The previous owner was letting it leak and topping off the fluid occasionally. There is a LOT of fluid in the engine compartment/undercarriage.

I eventually tracked down the source and I'm 99% sure it's coming from the brake booster. I was just about to replace it, but a guy at the bar mentioned it could just be o-rings from the connecting lines. I figured I would try that first since the parts are $300+ and it's fairly easy to remove/install.

Does anyone know the o-ring sizes I would need to get?

Or any advice in general with this issue.

 

[ORVietVet]

Welcome to the forum from Oregon. Should have a separate listing at a parts store for seals or at RA.

I would bet if you look under dash, where the rod comes thru the firewall, the housing is wet and typically leaks at accumulator on engine side. Unless lines are loose, the o-rings hardly ever leak.

 

[4silverado]

Just to throw something else out there that could be a leak source , my 04 had a pinhole leak on the back side of the oil cooler (it sat on left side between the grill and core support). It managed to spray oil through the rubber around the core support and soaked down the battery and left fender well. I still don’t understand why the fan didn’t get ahold of any oil and sling it all over the engine bay. That cooler is like a 2-row oil cooler. All I did was bypass the cooler. I’ve been running without one for close to 6 years now. I can’t tell that it’s made any difference with or without the cooler there.

 

[4silverado]

I had to go find the post on another forum; it was November 2018. I ended up cutting the return line about 2 inches back from the steel line where the hose ran from the cooler to the rack. Usually, hydraulic hoses and tube assemblies have a hose barb that extends into the hose a couple of inches; I made the cut far enough back to miss the hose barb. I then looped this line back to the pump and reinstalled the hose clamp. I wanted to leave the longest length of hose possible, since shorter hoses have a tenancy to kink. It has been working fine since repair. Pump seems good and no issues with the rack so far.

Looking into replacement coolers back then; OE /Dorman from Rock Auto was the cooler and lines for $150-170. Summit Racing had a small single row cooler, hoses and hose clamps for less than $25. Probably go this route but it'll be once things warm up.

 

[4silverado]

Even if you don’t buy from Rock Auto, it is a very good source to price match / see what is available before going local.

 

[ORVietVet]

Just to throw something else out there that could be a leak source , my 04 had a pinhole leak on the back side of the oil cooler (it sat on left side between the grill and core support). It managed to spray oil through the rubber around the core support and soaked down the battery and left fender well. I still don’t understand why the fan didn’t get ahold of any oil and sling it all over the engine bay. That cooler is like a 2-row oil cooler. All I did was bypass the cooler. I’ve been running without one for close to 6 years now. I can’t tell that it’s made any difference with or without the cooler there.

I had to go find the post on another forum; it was November 2018. I ended up cutting the return line about 2 inches back from the steel line where the hose ran from the cooler to the rack. Usually, hydraulic hoses and tube assemblies have a hose barb that extends into the hose a couple of inches; I made the cut far enough back to miss the hose barb. I then looped this line back to the pump and reinstalled the hose clamp. I wanted to leave the longest length of hose possible, since shorter hoses have a tenancy to kink. It has been working fine since repair. Pump seems good and no issues with the rack so far.

Looking into replacement coolers back then; OE /Dorman from Rock Auto was the cooler and lines for $150-170. Summit Racing had a small single row cooler, hoses and hose clamps for less than $25. Probably go this route but it'll be once things warm up. View attachment 2424

To be clear, you are talking about a steering gear box or a rack and pinion? If is rack and pinion, is it because is a 2wd?

 

[4silverado]

To be clear, you are talking about a steering gear box or a rack and pinion? If is rack and pinion, is it because is a 2wd?

Thanks for reminding me about that. Mine is 2WD. OP might have 4WD which would be a different setup.

 

[ORVietVet]

Thanks for reminding me about that. Mine is 2WD. OP might have 4WD which would be a different setup.

I had no idea the 2wd had the rack and pinion till I checked the application. I gotta stop assuming.

When you first said "rack" I immediately thought of my 2004 K2500HD and knew I had a gear box but I looked up the application.

It is so nice when the members put their vehicle info in their signatures.

 

[ORVietVet]

To @mayvillain, I would bet that your hydro-boost is leaking at the accumulator and since I am also betting that it is seeping/leaking inside the cab, under the dash where the rod that attaches at the brake pedal, comes out of the back of the hydro-boost. Very common. I know. Mine is and I will be replacing the hydro-boost. You can leave the brake lines attached to the master cylinder and remove the two 15mm nuts and pull it away and look to verify that there is no leak at the back of the master cylinder. The hydro-boost is not that hard to replace. About 1 hour and will need a refill of p/s fluid to top off and bleed system. Check this video out from South Main Auto LLC from you tube. Pay close attention to what he says about the lines and o-rings at the booster. If you do the booster, it is the perfect time to do the stop light switch replacement too. This guy does great videos:

If you do decide to replace the lines, the one on the engine side of the hydro-boost that goes to the back of the p/s pump, is a booger. Check some videos out for that too. There is another video on you tube for bleeding the system out if you do lines and dump the system.

This bleeding video is how I was taught by a wise old man at Kaiser Brake & Alignment in Eugene, Oregon.

 

[someotherguy]

Another common source for hydroboost-related leaks are the lines themselves, once they get some sufficient age and miles on them. You'll want to degrease the area thoroughly and run it a short while to see where the leaks are.

Richard

 

[ORVietVet]

Another common source for hydroboost-related leaks are the lines themselves, once they get some sufficient age and miles on them. You'll want to degrease the area thoroughly and run it a short while to see where the leaks are.

Richard

When you do this, make sure to remove the convoluted tubing from the lines and then clean off. Pressure washer works best. Then drive with lots of braking and turning to force the fluid thru the lines. Suspect places are where the lines themselves rub and at the crimp fittings.

 

[mayvillain]

To @mayvillain, I would bet that your hydro-boost is leaking at the accumulator and since I am also betting that it is seeping/leaking inside the cab, under the dash where the rod that attaches at the brake pedal, comes out of the back of the hydro-boost. Very common. I know. Mine is and I will be replacing the hydro-boost. You can leave the brake lines attached to the master cylinder and remove the two 15mm nuts and pull it away and look to verify that there is no leak at the back of the master cylinder. The hydro-boost is not that hard to replace. About 1 hour and will need a refill of p/s fluid to top off and bleed system. Check this video out from South Main Auto LLC from you tube. Pay close attention to what he says about the lines and o-rings at the booster. If you do the booster, it is the perfect time to do the stop light switch replacement too. This guy does great videos:

If you do decide to replace the lines, the one on the engine side of the hydro-boost that goes to the back of the p/s pump, is a booger. Check some videos out for that too. There is another video on you tube for bleeding the system out if you do lines and dump the system.

This bleeding video is how I was taught by a wise old man at Kaiser Brake & Alignment in Eugene, Oregon.

So it is indeed the booster itself that is leaking, not the lines. It's leaking on the bottom in the back, right where the main housing bolts together. Seems like an easy enough fix, although the part itself is a little pricey.

Thank you for the advice and the video!

 

[ORVietVet]

So it is indeed the booster itself that is leaking, not the lines. It's leaking on the bottom in the back, right where the main housing bolts together. Seems like an easy enough fix, although the part itself is a little pricey.

Thank you for the advice and the video!

Yea, I can see the Genuine GM $657 booster at RA and if you have the money, it is the one to get, but the Bosch is a great substitute for a much better price.

https://www.rockauto.com/en/moreinfo.php?pk=13977153&cc=1380282&pt=1884&jsn=1165

In my case, I am always gonna choose an OE GM part, even at that price but it is not available for my 2004 K2500HD 6.0 Silverado. I ordered the Bosch. I even looked at other Genuine GM parts suppliers and at ebay with no luck.

 

[stutaeng]

My beater 2000 OBS K3500 had/has a leaky mess. The PS would leak about 1 qt. in about 60 miles when I had just got it, LOL. Mines were the lines. I had my son turn the steering wheel and there was this massive leak! I can't remember if I replaced the hydroboost unit on that one; I think I did?. But I replaced all the leaky PS/hydroboost lines and they come with the little o-rings.

The instructions on the new lines do say to replace all lines because they degrade from the inside out. Makes sense, I guess.

I had had a leaky PS line on my 99 Silverado as well, but wasn't as bad. That one has the vacuum assist brakes with rack and pinion, but same thing applies.

I would take the opportunity to go a head and replace the PS fluid and do a full bleed. Likely the fluid is past it's service life. Get new, fresh fluid into the system.

OP mentioned an 8.1, so that would be a 2001+ 2500HD with torsion bar/gearbox steering (even the 2wd version) and hydroboost brake system...

 

[ORVietVet]

When the line degrade from the inside, there will be the line material debris that will travel/float in the system. If you can afford to do the lines, do them and a full bleed sequence, like in the supplied video.

 

[mayvillain]

Also, quick update:

I decided to try my luck with a rebuild. I bought the $35 seal kit from Pirate Jack; heard it was a little better than A1 (or whatever).

My expectations are low, but since it’s an accessible part and I’m short on money I figured id try that before dropping $650 on the booster unit.

I’ll update once it’s in and road tested.

 

[ORVietVet]

Also, quick update:

I decided to try my luck with a rebuild. I bought the $35 seal kit from Pirate Jack; heard it was a little better than A1 (or whatever).

My expectations are low, but since it’s an accessible part and I’m short on money I figured id try that before dropping $650 on the booster unit.

I’ll update once it’s in and road tested.

If you notice in the video, he was dealing with a reman unit and had to swap over the push rod at front of the booster unit. From old to the reman one. The keeper clip keeps that spring in there. Be very careful when you remove the keeper clip because when that clip lets go, that spring flies out of there. It will ruin your day and maybe the whole weekend.

 

[Cadillacmak]

Also, quick update:

I decided to try my luck with a rebuild. I bought the $35 seal kit from Pirate Jack; heard it was a little better than A1 (or whatever).

My expectations are low, but since it’s an accessible part and I’m short on money I figured id try that before dropping $650 on the booster unit.

I’ll update once it’s in and road tested.

If it can be rebuilt, do it! I miss the days when the parts store carried as many rebuild kits as they did new and re-man parts.

 

[ORVietVet]

Too many times, after removing the component, tear down and rebuilding the component, reinstalling the component and then hoping that the rebuild will work, and if did not work, an owner reflected on the wasted time and wished they bought a reman unit to begin with, to save time and effort and maybe even money and still get some sort of warranty.

In the 70's, I diagnosed starters and alternators failures and rebuilt them. Then the "time saving" started with reman units.