Try measuring the rod and/or double check for the correct pedal. Might fix the pedal being too high. I can take pics of the correct pedal with Silverado hydroboost. Unfortunately I didn't take any of the pedal with the van hydroboost. I think the main difference between accumulators are the amount of stops you can do after cutting the engine.

 

If you try to use the non hydroboost pedal it will be higher, in theory same with the van hydroboost.. The pivot points are at different heights on the shank of the pedal... Which in turn accommodate for the rod length....

 

I'm in the process of doing this for a 98 K1500, if anyone is interested, I have photos. some highlights:

-NBS pedal won't work, but the stock vacuum pedal in my 98 seems to work fine, despite the slight difference in location.

-stock brake switch works fine

-the rod length is different, as previously noted. BUT: the Express van unit that was used in post #118 of this thread will work without modifying the rod, as it has the same or very similar rod length to an OBS (from what I see in the photo, 1/4" difference or less, maybe none.)

-you can still use the shorter rod length unit, but you have to cut the eyelet off the shorter rod, thread it with a 3/8-16 die, and then measure your stock booster's rod length, cut off the appropriate amount, thread it as well, then join both halves with a coupler nut. this gives the added benefit of adjustability if you need it.

-the 2004 Suburban booster (the one I used) fits both the larger or smaller bore master cylinders.

-stock NBS lines may work, or may not, it depends on your truck, but were too short for my truck. if you need longer, either use a line from a 95 K3500 with a 7.4L or 6.5 Diesel, or use 2002 Silverado 3500 with 8.1L for longer lines. Some lines give you more length in the metal line, others in the hose section, hence the two applications - one of them WILL work, I used the 2002 truck application with almost no bending at all. call it a little nudge.

If anyone wants more info, I'm happy to share. I haven't seen anyone do this before, so I'm trying to get the info out there for folks.

 

Thanks for the info!

 

No problem! For the love of the hobby and all that. I couldn't find ANY info on it, or on swapping the NBS gearboxes in an OBS truck, so I figured I'd just do it and see what happened. I have to put an oil pump in today, then I'll refill all the fluids and bleed the power steering and try it. But seriously, I have photos too, I'll post them later today if you want. FWIW, it really looks like that Express van unit would bolt RIGHT into an OBS, the rod length looks damn near identical to the ~7.5" I measured from my 98 vac booster, which is what I based my rod length on.

Also, what fluid is everyone running? ATF or P/S fluid? I can't get a definitive answer other than the GM part # for P/S fluid. maybe that IS my definite answer - p/s fluid.

And is anyone running a bigger cooler? I have a 12x12 plate cooler, but I read somewhere, probably in this thread, that those weren't good. I have both the NBS and the OBS cooler and I can put those on the truck easily.

 

Came here to say this. Tech like this is what makes this site great!

 

the NBS hydroboost swap into my 98 ECSB K1500 is a complete success. if you want details, I can put something on the thread. The punchline is that the NBS HB unit is completely viable for this swap in an OBS, it does take a little more work, but if you have a decent set of tools or access to things like a tap and die set (or at least a 3/8-16 die) then you can totally do this. I used my stock pedal and a reman'd hydroboost pump, a junkyard-sourced HB unit, new pump to booster line, hydro fittings to plumb my winch in lieu of a booster to gearbox line, and a stock OBS cooler (though you can use any power steering cooler or trans cooler so long as it isn't a plate-style.)

 

Picked up everything but the lines today for $50. I have a 2wd with a rack. Did I read correctly that I need lines from a van to work properly?

 

no the truck lines work fine

 

I would like to add hydroboost to my 03 silverado ext cab. Which booster makes the most straight forward install? On my turbo truck I believe I got one from a 2500HD and it was very easy and no issues.

I found one in an 04 tahoe and it has the motor thing on the brake pedal and I also found one in an Avalanche. Do those work okay or is it better just to get one from a 2500hd?