Strange stuff with hydro-boost

[rv8pilot]

This weekend I did a vacuum boost to hydro boost conversion on my 2001 Yukon XL. The AC Delco Reman HD unit and AC Delco hoses came from RockAuto shipped for under $180. Miscellaneous bits were picked up locally. Total cost was $210. Installation was reasonably straight forward with the usual hiccups. If anybody wants part numbers please post.

The system works well, not as powerful as I expected from this and other forums but perhaps that's a matter of the size/original application of the HD unit. Mine was for the '01 Yook. Brake feel is much better though, the pedal is more solid and stopping power is improved, just not by a humongous amount. I'm happy with it.

Here's the odd thing: I have been considering getting new pads and rotors because of annoying pedal pulsation like with warped rotors. During my test run today it dawned on me that I wasn't getting the pedal pulsation. I tried different speeds and braking loads and could not find any trace of pedal pulsation. Go figure.

Not only that, in an earlier post I complained about the steering being too light on the highway, and guess what, it doesn't seem as light now. Maybe the HD is absorbing some of the PS pump pressure all the time. Or maybe I'm just losing it.

 

[drakon543]

Its only a concern when you start talking to yourself and the voices in your head answer back.

 

[Rocket Man]

This weekend I did a vacuum boost to hydro boost conversion on my 2001 Yukon XL. The AC Delco Reman HD unit and AC Delco hoses came from RockAuto shipped for under $180. Miscellaneous bits were picked up locally. Total cost was $210. Installation was reasonably straight forward with the usual hiccups. If anybody wants part numbers please post.

Yes please post part numbers. I've only heard of doing this with junkyard parts.

 

[rv8pilot]

Well, I just refuse to do what they tell me

 

[rv8pilot]

Yes please post part numbers. I've only heard of doing this with junkyard parts.

Ok, here goes:


Part Number Part Type Price EA Core EA Quantity Total
2001 GMC YUKON XL 1500 5.3L V8
ACDELCO 14PB4048 (14PB4048@A25-OSTK) Power Brake Booster $ 119.79 $ 20.00 1 $ 139.79
ACDELCO 36365425 (36-365425@Z04) Power Steering Pressure Hose $ 15.21 $ 0.00 1 $ 15.21
ACDELCO 36365452 (36-365452@Z04) Power Steering Pressure Hose $ 19.69 $ 0.00 1 $ 19.69
Discount $ -7.73
Shipping Ground $ 10.99
Order Total $ 177.95

Obviously, if you can score an old HD you can save $20 by returning the core. I'm not crazy about reman stuff but at least there is a warranty of some sort. You will need about 3' of 3/8" fuel rated hose for the return line and a 3/8" tee to go into the existing return line. A quart of fluid, 5/8" hose clamps (4) does it for the small stuff. You will need a new pedal as the HD centerline is quite a bit higher and the stroke is shorter (I think). I got mine from GM Parts East with the following p/n:


Part No. Description Price Qty. Subtotal
15906961 PEDAL 19.98 1 19.98

Subtotal $19.98

Tax $0.00

Shipping & Handling $13.56

Total $33.54

There is an excellent write up with pics on: http://www.gmfullsize.com/threads/hydroboost-install-how-to-with-pics.156800/

Your mileage may vary but I had to grind away about 1/8" arc of the top of the hole in the firewall to allow the HD unit to sit flush. Since references to a 1/2" spacer were made in the referenced write up I made one ahead of time out of a piece of 1/2" plexiglas. It turned out not to be necessary as it made the pedal much too low. Removing it put the pedal at a good height. If anybody would like to have it, let me know.

The write up discusses drilling a new hole in the firewall or pressing out the stud. I decided to try pressing out the stud as there was a molded piece on the inside of the firewall I didn't want to damage. It was difficult to remove. I used a 2 ton arbor press and beat the crap out of the ram with a lead hammer to get it out. I redrilled the hole 10mm in mounting plate and pressed the stud back in. Its not perfect but its not gonna fall out either.

 

[bottomline2000]

that's a nice price for an all new setup!! I'm sure I paid as much or more for used. I had a problem with bleeding air out my system for a while. Once it was all out the hydroboost worked great. look for bubbles or foam in the power steering pump reservoir. Also I changed the fluid since it got dark fast, but I had used HB parts with a new power steering pump.

 

[Rivieraracing]

Thank you very much for this thread, the part numbers of what all is needed is most appreciated! I'm hopefully going to do the front brake '07 upgrade soon since I have all the stuff for it, then I'll do what you did!

 

[rv8pilot]

My pleasure. I'd love to do the '07 brake thing myself but for now I'm stuck with the 16" wheels as I just bought new tires. Guess I could sell them but I'd take a hit.

I checked on the difference in centerline height between the vacuum booster and the HD and the HD is 3/4" higher relative to the bolt pattern. I think if one tries to use the old pedal the angularity of the pushrod might be too great causing a bind in the HD. I think the HD has a shorter stroke requiring shorter geometry in the pedal. Probably a spacer would be necessary to adjust pedal height as well. Just my humble opinion.

 

[Rivieraracing]

Good to know, I'll try to remember to post up on here when I do both the brake upgrade and the hydroboost together! The braking on these trucks suck so hoping for good results with both!

 

[rv8pilot]

Something else regarding the gmfullsize write up: My Yukon only has the factory fiberglass belly pans and there is plenty of access to the rear of the power steering pump to detach the pressure hose. It is not necessary to dismount the PS pump. Also, the hose fittings are 16mm & 18mm, I found a flare nut wrench at NAPA with both these sizes on one tool, looks like the had GM in mind. However, the pressure line nut on the top of the steering box was impossible to loosen with the short flare wrench because of tight access. If you have the radiator etc., out it would be easier but I used a crowfoot flare wrench with enough 1/2" extensions to get above the bodywork in order to get the leverage I needed. You will be discarding the old hose anyway so do whatever works to get it out. It could be cut off and a socket pushed over the nut, just don't get metal into the pump.