Bad Brake Booster?

[Mark Brye]

Hi Guys, need some advise. I have BDR354 which I have about 6000 miles on. I went to pull out of the garage today and had no brakes. The pedal is hard as a rock. There are brakes but I would be better off dragging me feet to stop the car. My first thought was either my electric vacuum pump stopped working or I lost a line between vacuum pump and booster. I pulled into the garage and turned off the engine and turned off the fuel pump so I could here if the vacuum pump was working.
I pumped the brakes and my vacuum pump turned on, created vacuum and then shut off when it reached full vacuum. It held the vacuum for half an hour without turning back on. At this point I tapped the brakes, putting the pedal in mayby 1/4 of an inch and you could hear all the vacuum whoosh and bleed off instantly and then the pump would turn back on. In the past I could get 4 good pumps on the brakes before pump would turn on. Now, if I just touch the brakes I loose all my vacuum. Does this sound like the brake booster has an inernal leak?
Any one know what the p/n is for this build number 354? Thanks!

[Mark Brye]

So I ordered a new booster from backdraft parts. The one for the RT3 is evidently larger (10 inch) than what my older car has. Mine is about 8.25 inches in diameter and I only have about a 1/4 inch clearance between booster and steering shaft so I cannot go larger. They are trying to source one for me.

I wish I knew what the part number was or the vehicle it was sourced from. All I know is that it was made by ATE.

[Cashburn]

The story as it has been told to me...

The original boosters were produced by ATE. About 2 years ago the machine they had that produced these mini boosters went down. They opted to not repair it or replace it due to the very low volume it was getting in sales.

And now we have the bigger booster.

It will take some ingenuity no matter how you slice it.

[Cashburn]

These are small. Have not tried the retrofit yet... but an option:

http://www.speedwaymotors.com/7-Inch...ster,8446.html

[Mark Brye]

Thanks for your help Jay! Hopefully Backdraft parts will be able to find one in a pile of parts somewhere. I will checkout the one from speedway motors also. Looking on line I see that there are places that rebuild also. That may also be an option....

[1blackbb66]

Looks like Speedway is the way to go bud. They have several that are 7" OD.

Ray

[Mark Brye]

Update, well kind of.. I sent the booster to a booster rebuild place on the west coast. They are not able to rebuild it because they cannot identify what booster it is other than the size and that it is made by Ate. Still waiting to here back from BDR to see if they have found one.

In the time being have been looking at new boosters. The boosters from speedway have a single diaphram 8" about the same size as my bad one. Or I could get a 7" dual diaphram but it is a couple inches longer and would put it closer to headers. To do either, I will need to drill new holes in fire wall and also get a new master cylinder. Also I will have to bend new brake lines and fittings to match.

I have the wildwood bbk kit on the car. The instructions for the brakes say that a 7/8, 1" or 1 1/8 inch tandem booster is used for this brake kit. What size should I get? Not sure would size the existing master cylinder is. It seemed to work fine.

Jay, what size booster would you get and do you have an idea on what size master cylinder to get?

Thanks

[Mark Brye]

Originally Posted by 1blackbb66

Looks like Speedway is the way to go bud. They have several that are 7" OD.

Ray

Ray, I will have cold beer ready for you as usual. Just need to get some parts here so you can sit in the drivers seat and pump the pedal with a cold one in your hand!

[Brooklyn-427]

Its a BMW brake booster maybe E30 or E36 series

[Cashburn]

Ask the rebuild shop if they can match it with an 86 Corolla. What is the ATE number on the box they sent you?

[Mark Brye]

Originally Posted by Cashburn

Ask the rebuild shop if they can match it with an 86 Corolla. What is the ATE number on the box they sent you?

I can ask the rebuild place but they have already shipped my blown booster back to me so it's in the mail. The booster does not have any markings on it except for part of a torn off label that ends in I think 200. It is stamped Ate on the front and its 8 inch in the front and about 8.5 inch where the back is crimped on.

I have looked at e30, e36, 2002, Audi, vw, Porsche, mb and such euro cars to figure out what it's from. Also tried to check out some toyota's. So far no luck in finding a match.

[jimbo01]

Should you find a match for the ATE booster it would be good to know. My booster is also about 8 1/2" also. It seems that the clutch is moved over to make room for the larger booster. That would require a lot of work unless your building the car.

[Brooklyn-427]

This could be a good lead , they will not specifically know what a Backdraft cobra is however they could give you possible makes and models as too the orgin of your servo booster by size .

ATE Brakes - Euro Car Parts UK

[Brooklyn-427]

how about this one

https://www.vwheritage.com/shop/2816...ter-t25-80-92/

[Mark Brye]

Update - Backdraft parts was able to find me a booster that was pretty close to the one that came on my car. Its an ATE. P/N 3.6130-6500.4. There are other markings under the part number which may be a version number or something. (T51. 161 1 H 5 F ). It has same bolt pattern as my factory unit. It's just under 8 inches diameter. Maybe a 1/4 inches thicker. Everything mounted up fine. This booster required backdraft to have to thread the booster rod all the way down. I had to cut the rod shorter for correct pedal travel. I also had to chase the threads M12-1.75. (I should say that Ray did all the hard work chasing threads and cutting). The booster rod is bigger diameter and has a bigger Clevis pin so you have to drill out pedal arm for bigger Clevis. This requires a right angle drill and stubby bit in the small confines of the foot box. Ray cut down a bit and ground down the bit to fit the drill we had. Only other issue is that the shape of booster is a little different so my older style heat shield does not fit anymore. Will probably try the heat shield on backdraft parts website. I also replaced the gasket between booster and master cylinder. I will post the p/n for that also. I have not driven car yet but am getting close. big thanks to Ray (BlackBB427) and John as always for helping me wrench.

[Mark Brye]

Oh it was Ray - 1BLACKBB66 that is my master wrencher.

[Mark Brye]

Originally Posted by Brooklyn-427

how about this one

https://www.vwheritage.com/shop/2816...ter-t25-80-92/

Thanks for the links. I think on the older cars, that 9 inch diameter might be to tight. I mached up a 9 inch can and could not get it to fit. Might work on others cars though as it was very close.

[Tomcobra17]

I have Car #188 and the following is the information on the white sticker on the brake booster:

ATE
07.7742-1441.4
085 4B T52/4/200
47210.B1002A

I hope this helps!

Tom

[Tomcobra17]

I have Car #188 and the following is the information on the white sticker on the brake booster:

ATE
07.7742-1441.4
085 4B T52/4/200
47210.B1002A

I hope this helps!

Tom

[Mark Brye]

Thanks for the update. I wish I had that info. This will be really helpful for a lot of people with older cars.