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BC Broncos power brake kit

Wyflyer

Bronco Guru
Joined
Apr 1, 2008
Messages
2,920
On my 72 halfcab project i'm trying to get good brakes. Everything is new and now i'm bleeding it up and trying to make it all work. It has 79 Bronco front discs, with factory rear drums. The proportioning block is a new TBP disc front/drum rear valve block.
The master cylinder is a new BC Broncos master cylinder/booster kit with the angle bracket and bell crank for the brake rod.
It's all new parts.

When I put it all together I routed the large primary reservoir on the master cylinder to the front discs. The small front brake reservoir routed to the rear drums.

I bled it all and jacked it up on stands. After adjusting the rear brakes I then bled all 4 corners and ran it in gear on the stands to check braking. It doesn't have enough braking power to stop the rear wheels.

It doesn't act like the master cylinder booster is working. So I bled and pumped it again and still no brakes.
The brake pedal would not return back to height, and now the end has broken off the bell crank where it goes into the brake booster and shattered the plastic boot shroud where the push rod enters the booster.

I think the booster is not working or the piston is stuck or something? I'll get with BCB this week and see how to repair or replace the booster kit.

Why would the pedal not return to correct height with the system bled and good vacuum to the booster?
Help me out here please this has me scratching my head...
 
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Wyflyer

Wyflyer

Bronco Guru
Joined
Apr 1, 2008
Messages
2,920
End of week report:
I decided to do a complete review of my parts to make sure it's all compatible. I made some phone calls to vendors and found out I bought the proportioning valve from WH not Tom's. It's the correct proportioning valve for my disc conversion with drum rears. The lines in and out are oriented correctly.
The vendors gave some good advice ref bench bleeding and master cylinder sizing for calipers.
BCB were great, they shipped me a new brake and booster kit. Jason advised he prefers this master cylinder/booster kit to be used with T-Bird calipers but should work with my 79 Bronco discs. The kit arrived yesterday & I installed it then built new lines from the master cylinder to the proportioning valve, insuring the big reservoir is plumbed to the front discs. I wasn't happy with the fit and look of my last set of lines.

So... when i tightened the flare nut into the brass proportioning valve one of the lines turned in the brass and scored the brass seat, so it won't seal now. So i've ordered a new proportioning valve.
And the leaked brake fluid from all this line changing has bubbled the new frame paint. It's never moved on it's own power yet and already needs paint repairs.
The vendors have all been great, but this damned thing is trying my patience.
 

Rustytruck

Bronco Guru
Joined
Feb 24, 2002
Messages
10,875
Well the horse is out of the corral now but next time take some aluminium foil and put under brake parts your working on. it molds easily and stays in place without allot of hassle. Same thing when you go to repainting stuff in tight places. You can mask off hoses and brackets with foil and then spray around in tight areas. I used allot of foil when painting the engine bay with the compartment intact with stuff that wasn't easily removed or moved out of the way.
 
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Wyflyer

Wyflyer

Bronco Guru
Joined
Apr 1, 2008
Messages
2,920
great advice, I will use this! when i repair the frame paint. Thanks
 
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