Hydroboost leak '03 2500HD

[03silverchevy]

Anyone experience a leak from the hydroboost unit? Has anyone replaced it? how long did it take? pictures?

[DmaxMaverick]

It depends on what you mean by "leak". They will seep a bit over time, usually around the accumulator (the aluminum cylinder on the inboard side). Most of the time, it's normal (not to be alarmed about). A serious leak will usually cause a fluid drip on the inside of the firewall (below the brake pedal), requiring replacement. If you clean it up and it doesn't get messy again for a month or two, just clean it once in a while and keep an eye on the fluid level. Also, verify it isn't a fitting that's leaking, which can be stopped.

Replacement isn't bad, but will take a couple/few hours, depending on skill and how many times you've done it. It mounts the same as a gasser vacuum booster, with the studs through the firewall, nuts above the brake pedal and steering column. Hard to reach if you aren't limber, but not bad.

[03silverchevy]

After driving the truck and parking it in the street I get a 4" dia puddle directly under the PS pump. I traced the hoses back up to the booster and it's leaking at the flange for the booster. I have PS fluid all over the wheel well.

How much would I be able to find the part for? I've found the booster for anywhere from $315 to $520. Are rebuilds reliable? would the price difference be rebuild or new? The dealers ( I checked 2) said they were both new.

[DmaxMaverick]

That leak is significant. However, if it is leaking at the flange, it should not be dripping under the PS pump, or on the wheel well. It is more likely a line fitting or crimp. There's no way for fluid to get from the HB unit to the PS pump area unless fluid is sprayed in that direction, in which case, everything under the hood would be covered with fluid. The 3 lines are connected at the top of the unit, and fluid won't flow uphill (which is the only way fluid will flow from the HB unit to the PS pump). I would suspect the fluid you are finding at the flange is coming from somewhere else, or you have more than one leak.

The amount of fluid you are seeing should not be hard to trace. I suggest cleaning it up and watching for the source. Use a good degreaser, then dry it up real well with some brake cleaner.

[03silverchevy]

It looks like there are two different leaks- the hose at the ps pump and the hydrobooster. Now, WHY did I have to take it to the dealer for them to tell me that... Well- I am kicking myself for that one...
The dealer tech indicated they don't get much work on the Duramax's. I may have to find a dealer that works on these trucks a bit more. If it is just the hydrobost and the hoses, I most likely can change it out myself.

[DmaxMaverick]

The hydroboost system isn't unique to Duramax trucks. The system has been used on GM trucks (as well as others) for over 30 years, essentially unchanged from day one. If your dealer has a problem understanding the basics of the system, they just emerged from a cave (or worse).

I suspect you have a "major" leak at the hose(s), and a minor (possibly negligible) leak at the HB unit. Neither are unusual. I suggest replacement/repair of the hose(s), and a closer look at the HB unit leak to determine the seriousness (decide if it warrants replacement). Adding a little ATF conditioner (about 2 oz. of Trans-X, Trans-Medic, etc.) will often cure leaks at the unit. It depends on where it is leaking, and how much.

[03silverchevy]

I torn into it today and found the return hose from the booster to the pump had a pinhole in it. Will replace with new hose. Anyone know the part number?

[DmaxMaverick]

The part number should be printed on the hose. Otherwise, send a message to www.gmpartsdirect.com (use this link (https://secure.gmpartsdirect.com/secure/customer_service/)), and they'll ID it for you. Provide as much info as you can, including the full VIN.

[chipper]

I torn into it today and found the return hose from the booster to the pump had a pinhole in it. Will replace with new hose. Anyone know the part number?

Having a local parts house replace the hose on the old fittings will save you quite a bit of money.

[DmaxMaverick]

Having a local parts house replace the hose on the old fittings will save you quite a bit of money.

It's a return hose. No fittings, but it needs to be molded, or they kink (OEM hose). Try off-the-shelf hose and bend it at your own risk. At some time, and not a convenient time, it will kink. When it kinks, it will cause the return to overpressure, blow off the hose, and make a big mess. Not to mention leaving you w/o power brakes and steering before you realize it.

[03silverchevy]

I found the right part number using gmpartsdirect, VIN etc. Salespeople were very helpful- part was $43, labor was about an afternoon of getting greasy