Unknown brake part

[Snowturtle]

It sure doesn't look like there is anything connecting those two systems under my hood! Thanks. I'll look into the auxilliary vacuum pump. Why doesn't it show up in brake diagrams yet it affects my brakes? Is it purely for boosting the vacuum system and my brakes are vacuum assisted? Is that pump connected to my brake booster or just mounted to it? I haven't taken it off...

---------- Post added at 07:32 AM ---------- Previous post was at 07:12 AM ----------

So I searched for an auxilliary vacuum pump online and still can't find it. WTF?! Why is this thing so hard? Is my car the only GM that this was ever put on? Any suggestions? AARRGG!

 

[SLCHOE]

From your inital description I assumed you were talking about the accumulator on the hydroboost unit but it's clear you don't have hydroboost. I'd look into the aux vacuum pump as the other member said. It would make sense since low vacuum would affect your vacuum brake booster.

 

[big_b_in_PA]

I have been looking around online, I can't find any of these at all. I'm wondering of there's a way to bypass or eliminate that pump. Hopefully somebody else has had this issue and can chime in with advice.

 

[SLCHOE]

What does the other side of the aux vacuum pump look like? How does it connect to the brake booster? If it's connected by a hose, you could try bypassing the pump.

The only thing I could find about it was from Mitchell On Demand. All it says is that if it's noisy or inoperative, replace it. Couldn't find a parts source anywhere. You may try calling a dealer and see if you can get a part# from them. Speaking of part numbers... is there one stamped on it anywhere?

 

[Gatorlac]

My bad....thought they started using them in 03 and never looked at the pic

 

[Snowturtle]

Dang, I never thought this thing would be so complicated! I haven't pulled it off of the brake booster to see if it is just hanging on there or if they are connected somehow. The large vacuum line goes to the back of the intake manifold, the other smaller line goes down the firewall below the brake booster but I haven't followed it yet. I also didn't follow the wires yet. It's dark when I leave for work and dark when I get home so I've been waiting for a good time to delve into it, just wanted to do my research first. There is a sticker on the side with a very faded number that I can't read. It is definitely involved with the brake system because it only hums when I press and release the brake pedal and the brakes are soft until it has warmed up enough to quit doing that.

 

[YukonXL04]

I can't say that i have seen that on a NBS before.. Wonder if it was added at some point.

 

[big_b_in_PA]

This is the only thing I could find, I looked for the part number, and it's a discontinued part.

The link for the part: http://parts.nalleygmc.com/products/PUMP-Vacuum-Power-Brake-Pump/3113632/89058946.html

 

[Snowturtle]

Thanks Big B, that's at least a good start. I'll see if I can find one at a junkyard maybe.

 

[SLCHOE]

The part number was superceeded. The updated part # is 89040236

http://www.tonkinonlineparts.com/p/GMC__/PUMP-Vacuum-Power-Brake-Pump/6273736/89058946.html

http://www.tonkinonlineparts.com/showAssembly.aspx?ukey_assembly=848651&ukey_product=6273736