Mine is leaking and I cannot locate oem/acdelco replacement. Any specific brands I should consider or avoid?

 

You might also consider having your original one rebuilt. There are still shops around that will do this, I had it done back in '23 for my '74 Cutlass (which uses a rare BBO booster for which there are no cores or off-the-shelf aftermarket rebuilds available). The shop I used was local to me and they did a fantastic job, will probably last another ~50 years.

On the other hand, I did buy an off-the-shelf rebuilt one for my '71 Nova from O'reilly (I think their brand is Brake Best?) back in 2014 and it's still doing great too. These will usually come with a rust proof coating that is temporary, so if you want the finish to stay nice you'll need to remove the coating with brake & parts cleaner, and then paint the booster yourself. This is what I did for my '71 but, looking back, I really should have bought one that came with the proper cadmium (I guess it's Zinc Chromate now) plating as it is a nicely restored car. For our 4th gens the booster is black so painting it yourself is easy.

 

RockAuto has remans for $132

 

I had the shop replace the brake booster with a locally sourced replacement on Saturday. They bled all four calipers in order as well as the master, using me in the seat to pump/hold the pedal. Not particularly happy with the pedal feel, unsure if it's failing memory, the booster, something missed in the install? Brake pedal is fairly soft for the top of the travel, the assist comes in quickly maybe 1/2-3/4 down the pedal travel. When at a stop, pressing hard on the pedal appears to have some sponginess. Tech thought the old booster may have had a slow leak, causing it to get firmer at the top of the pedal and skewing my perception of how the pedal should feel. He says the pedal feels normal for a vehicle.

 

Might be a good idea to have it vacuum bled. Sometimes manual bleeding won't get all the air out, and that might be why you're still not happy with the pedal feel. There is also something about needing to actuate the valves in the ABS module for a "complete" bleed, though I'm not sure how much this matters depending on just how much air got into the system. It's also possible that they didn't bench bleed the new master first, in which case that is most likely the reason that air is still in the system.

Not exactly sure what you mean here, but power assist should come in pretty much immediately as you press the pedal, it shouldn't be delayed until 1/2-3/4 of the pedal travel.

It sounds like something probably isn't quite right here, but my guess is that it has to do with air still being in the system. The bleeding method was probably inadequate to fully purge all the air.

 

Only replaced the booster.

 

I have replaced boosters without needing to disconnect the lines from the master on older cars where the booster is easily reachable; in these cases, no bleeding is necessary. I haven't done a booster on a 4th gen, but it looks like you'd have to get the master completely out of the way to do this (meaning disconnect the lines), rather than just wiggling the booster out without disconnecting the master from the brake lines. The fact that they were bleeding the system would suggest that lines were, in fact, disconnected. How much air got in the system? Was the master plugged or allowed to bleed out fully without being bench bled? Or did they manage to replace the booster without disconnecting the lines from the master (seems unlikely in this application)?

 

When I briefly looked at the engine bay while they were trying to remove the old, they had gently bent the lines up while leaving master connected. I do not know if they were bent more drastically later.

 

what bleeding method did you use? I recently used the bottle method with some clear hose and it worked like a charm. i was very pleased. i had been doing it the old fashioned way for years and will from now on always do the bottle method.