Brake Booster failures

[BillR1212]

Brake Booster - Summit Racing part Number LEB-A9 - LEED Brake booster

Vacuum Pump - LEB-VP001B

Ok Team - another trouble shooting question. Pretty sure I have a bad brake booster. As this happened last time. I'm concerned with whether or not I have two bad brake boosters and bad luck, or if the vacuum pump is causing a failure in the booster. I never had a brake booster fail before. I changed out my old one for a LEED Chrome piece since I needed a new master cylinder. For the second time since I installed the vacuum pump I'm having a stiff pedal and can hardly stop the car. Vacuum pump is working. System holding vacuum. Brakes were bled and re bled. Just had new Wilwood brakes installed and things worked great for a few days prior to the stiff pedal. Thinking it has to be the brake booster again. I'm about to order another one.

Anyone having issues with LEED products? Is there a chance that the pump is pulling too much Vacuum and causing it to fail? I'm not real familiar with how they work, but I called tech support and they said that once the booster has the vacuum it wants then the pump shuts off. So they said it's not likely that I have a failure form the vacuum assist. Just seems odd to me that since I"ve installed that I have had two failures now. Just looking for some feed back.

Thank you!!

Since things are better with pictures - I have the following posted in random order:

-Wilwood brake install
-Dakota Dash
-Testing Dakota Dash counters - 0-60 with a rolling start on new transmission with much lower stall. My 500 CI engine actually bogs down now with the sticky drag radials where as before it would shred them. I think I have to brake stand RPMs up and try again for sub 4 seconds. Maybe tonight. (had to lower stall because I drive it too much and ruined 3 transmissions with the high stall converter on the highway. I think the gear vendors install actually hindered me because it lowered RPMs too much so it was not locking up)

-COVID19 pandemic empty highway pull on the German autobahn. Definitely not the USA.  Got out of it early. might check out a 1/2 mile top speed event to see how it does with more room and wide runways. Had a ton left in it with the OD. hard to be good with such empty roadways.

[1 Wild R/T]

You bought a POS Chinese brake booster...  Failures are VERY common....

[BillR1212]

You bought a POS Chinese brake booster...  Failures are VERY common....

Admittedly I have not purchased any brake booster's prior to this. Looking at my options on Jegs and Summit it was more expensive than the rest, and seemed to be headquartered in Buffalo NY. LEED also stood out as a quality brand vs the generic summit options and others that were selling for half the price of the LEED unit. Based on that I assumed it was better. I tried to do some research on where they're made just now and couldn't find anything in a quick search. With that said, it wouldn't surprise me if it's tooled in China. I'm sure many parts on everyday things we own are made oversea's...Sadly

Along with your criticism, I'd like to think you would offer some suggestions that have worked well for you in the past?  A bit of knowledge sharing for the benefit of others. I'll of course search for some other manufactures in the meantime.

[BillR1212]

Our sponsored site Moparts.com seems to have Brake Booster Bendix Trapezoid 70-74 E 71-74 B. SKU: 456-PB8536-2

Seems extremely generic in the listing. After some digging it seems to come from a drop shipper in Asheville NC, where they claim to make the parts there. Has anyone used these with success in the past?

[1 Wild R/T]

These folks show one in stock... 

https://www.thewrenchmonkey.ca/products/auto-parts/cardone/5473701/

Honestly I wouldn't be surprised if they don't have one but I suggest you do the work to find one....

Thats a rebuilt OE Bendix booster... They worked for the past 50 years, I've installed quite a few to replace those fine Chinese pieces of junk....

Had one guy who insisted he wanted a new Chinese one... I installed three of them on that car, none worked.. In the end he accepted a reman OE Bendix....  Guess what? The first one worked... He paid for my labor for each install....

[BillR1212]

I'd completely expect to pay labor each time. Anytime I do not attempt a repair myself I give the shop full discretion to purchase the parts they would get as if it was there own. This has been helpful. Since we're going down this path. My master cylinder is LEED as well since it was a kit, should I replace that too? I kind of need something sooner than later.

If I"m understanding correctly Cardone would be your first choice? Followed by Bendix? I also noticed that the company that makes Bendix Booster on Moparts.com (MDM) will create custom labels for other drop shippers. It appears Summit has this same one, just branded with their name. SUM-760194 , It would be preferable as I need it shipped overnight if possible. If you're able to take a look at that part number I'd appreciate it. Otherwise I'll buy Cardone and play it safe.

Thank you again!!

[1 Wild R/T]

Cardone sells original vintage Bendix boosters that have been rebuilt....
What Summit is selling is a Chinese knock off of an original Bendix B body style booster...  Personally I'd try to source original stuff but then I also know all the little parts can hang up most guys... The Summit kit includes a bellcrank, dogbone & backing plate...

I haven't tried all of the newer Bendix knock off stuff, it may be Ok... I do know the earlier stuff like the one you already have are bad news...

I suggest getting ahold of Dr Diff, he does deal with the newer Chinese Knock off stuff & should know if it's better...

I just went to his site, he does sell the newer stuff so thats promising...  It's also cheaper than Summit... Whether he'd have it in your hands as quickly as Summit is questionable....

https://www.doctordiff.com/bendix-style-dual-diaphragm-booster.html

[1 Wild R/T]

BTW FWIW my first reply as kinda harsh, honest but harsh... I've been trying to steer folks away from those boosters for years & still they wind up getting bought....   And from what I can tell not much has changed...  Good Luck!

[BillR1212]

BTW FWIW my first reply as kinda harsh, honest but harsh... I've been trying to steer folks away from those boosters for years & still they wind up getting bought....   And from what I can tell not much has changed...  Good Luck!

haha - if we were on a AMG forum I'm sure you would have hurt my feelings and I would have retreated to my safe space. I don't want to buy crap parts either. It kept me from taking my car to the drag strip, and of course when your brake pedal is stiff, every driver in the world wants to fill the gap you're leaving for stopping distance then slam on their brakes.

I was visiting a old school car guy with about 25 cars in his garage yesterday. He said my stuff was shit too and to send him a list of parts and he will have a friend pull them off older cars. So maybe I'll do that if I can't find a rebuilt/new booster.

[BillR1212]

Cardone sells original vintage Bendix boosters that have been rebuilt....
What Summit is selling is a Chinese knock off of an original Bendix B body style booster...  Personally I'd try to source original stuff but then I also know all the little parts can hang up most guys... The Summit kit includes a bellcrank, dogbone & backing plate...

I haven't tried all of the newer Bendix knock off stuff, it may be Ok... I do know the earlier stuff like the one you already have are bad news...

I suggest getting ahold of Dr Diff, he does deal with the newer Chinese Knock off stuff & should know if it's better...

I just went to his site, he does sell the newer stuff so thats promising...  It's also cheaper than Summit... Whether he'd have it in your hands as quickly as Summit is questionable....

https://www.doctordiff.com/bendix-style-dual-diaphragm-booster.html

Thank you - I'll order the one you posted on wrench monkey. Just need to make sure it fits

[BillR1212]

I can't find Cardone - the Canadian site won't let me check out. Might have to roll the dice with the Dr. Diff knock off. I'll get a reman ordered for a back up when I can find it. One last question. Is there any reason to believe my vacuum pump is creating too much vacuum and causing these to fail? I don't know too much about them. I'm not sure there is way to lower the vacuum on the assist pump.

If thats not the case, then I'm fine with the two Chinese knock offs are the only reason.

[1 Wild R/T]

To much vacuum isn't what caused your booster to fail....  Lack of quality is...  FWIW How much vacuum does your engine pull?  I've pulled vacuum pumps off a few cars after replacing the booster with one that works properly... Most vacuum pumps are pretty noisy...

If you can get 12 in/hg you'll probably not need the pump... 

[BillR1212]

I'll grab a gauge and check today. I can't remember off hand. I put it on because after my Cam swap (which still seems mild) I was only getting a few seconds of easy brake pedal. We thought maybe the booster was going, and thats when we went Chinese on accident. after the new booster we decided that maybe the pump would help. It did at first, but then the boosters started to act up.

I'll pull vacuum at idle and report back. About to take a ride now that the rain has stopped.

[1 Wild R/T]

What happened to the original booster? If it's still around it might be a good idea to send it to Booster Dewey...

[BillR1212]

Left behind at a shop 800 miles away. No telling if it's in a parts pile or scrapped. I'd have to call my friend and see if we saved it. In hindsight I would have sent it back to preserve these old parts. I just always assumed newer is better. Not always the case.