Any way to "refurbish" brakeline seat in the junction block?

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The Artist formerly known as Turbo84
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I've had a weeping brake line on the main junction block since I put new lines on the car. Of course, it has to be the bottom line that is difficult to see, and routes across the crossmember to the RF wheel. I put another short, plugged line on the junction block to see if perhaps the problem was my crossmember line, or the flare seat in the block. It's still leaking after applying pressure on the brake pedal, so I'm guessing the seat is scarred. I suppose I'm not surprised if there are some seat issues, given how stinking hard it was to remove the original lines so I could run the new custom lines. So, before I spend the money on a new junction block, is there a decent way to refurbish the internal seat on this block?

Thanks,
Mike
 
Some years ago, after finding that 'junction block' with the switch/brown wire on it was total insisting on leaking after some attempts at repair....I just flat replaced it, with a T fitting for the front brakes, and routing the rear up to the m/cyl directly....been that way for some years now...

no brake switch telling me the pedal is LO, but dunno I NEED a idiot light to tell me that much.....

been fine,even through the HB conversion, and m/cyl change shortly after that....

:cool:
 
That is the stupidest thing you could ever do. Apart from giving rear proportioning the most important function of that junction block is to activate the brake pressure warning. It's called a combination valve for that reason.
The proportioning valve delays full line pressure to the rear so that when you're braking hard and vehicle weight moves to the front the rears don't readily lock up and you spin out of control. This is where it differs from a disc/drum one, that type also has a delay valve for the front, called a metering valve. This is done so the rear drums grab first and provide rear stability before engaging the front (same reason hi power go carts have rear brakes or a rear brake, it's only for stability)

No wonder you can easily lock your brakes with the HB, you have removed all that was done to keep the brakes from locking up when you least want it, you turned your car into a suicide plane if you ask me. I know what it's like to drive something like that, my 83 truck...no weight on the rear ale but complete system in tact w/ combo valve. Still the rears easily lock up in wet conditions, later models were equipped with a load adjuster and a crude form of rear ABS....and that wasn't because GM figured it was a neat gizmo.
 
Marck, I tore that 'valve' totally apart, still have it, took out the switch, the whole thing open for examination.....found nothing other than a pressure differential switch between F & R circuits....if one failed, the switch flips over and closes contact on grounding the brown wire, light the light just like on the ebrake lever....

I failed to see any 'proportioning' aspect to it....

never found any particular change in braking action, wet or dry since then....

I even played with it a goodly bit.....but my eyes don't lie, nor do my feet....and ass for that matter....all it was....was a early attempt at a NADER device...cheep and easy....proved nothing like the rest of his lawyer designs...

:rose::stirpot:
 
I've had a weeping brake line on the main junction block since I put new lines on the car. Of course, it has to be the bottom line that is difficult to see, and routes across the crossmember to the RF wheel. I put another short, plugged line on the junction block to see if perhaps the problem was my crossmember line, or the flare seat in the block. It's still leaking after applying pressure on the brake pedal, so I'm guessing the seat is scarred. I suppose I'm not surprised if there are some seat issues, given how stinking hard it was to remove the original lines so I could run the new custom lines. So, before I spend the money on a new junction block, is there a decent way to refurbish the internal seat on this block?

Thanks,
Mike

Have you ever seen the seat washers for AN fittings? I think they are made out of soft aluminum.

I'm guessing there may be something similar to this for those fittings?
 
I've had a weeping brake line on the main junction block since I put new lines on the car. Of course, it has to be the bottom line that is difficult to see, and routes across the crossmember to the RF wheel. I put another short, plugged line on the junction block to see if perhaps the problem was my crossmember line, or the flare seat in the block. It's still leaking after applying pressure on the brake pedal, so I'm guessing the seat is scarred. I suppose I'm not surprised if there are some seat issues, given how stinking hard it was to remove the original lines so I could run the new custom lines. So, before I spend the money on a new junction block, is there a decent way to refurbish the internal seat on this block?

Thanks,
Mike

Have you ever seen the seat washers for AN fittings? I think they are made out of soft aluminum.

I'm guessing there may be something similar to this for those fittings?

Brass block/steel nutz and lines....flare.....
 
Brass block/steel nutz and lines....flare.....

Gene, what does this mean? Is it an answer or a question?

Any car I seen has a brass 'proportioning valve' and in a rear drum/disc front car of the era I have to presume it WAS one, but these sharks being nearly the only 4w disc cars I have worked on in those years...typical flare fittings horn/flare on the line, nut behind and into a brass block...like any other fitting of the times....I have NEVER seen anyting similar to a AN fitting with or without any washers or O rings, and those 'valves' in sharks are nothing but line pressure signal switches....as if GM knew about possible 'pumping' actions from the factory tests in the early 60's or so....

and in automotive use, honestly never seen the need for any change on line fittings......but that is another issue entirely....:D
 
67-76 were just a junction block with the switch
In 77 they changed to proportioning valves.
You guys are both right.
Mike
 
Gene, I wonder if your brakes would benefit from the proportioning valve. With your Hydroboost I expect the rear to be a little twitchy when braking on wet roads.
 
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Gene, I wonder if your brakes would benefit from the proportioning valve. With your Hydroboost I expect the rear to be a little twitchy when braking on wet roads.

Never had a problem....dunno, driven in rain many times, never felt anything strange, course I don't panic stop in the rain all the time either...

benn raining every day, maybe take it up around the corner and see, ....

new level road.....

:)
 
For early C3's and I suppose C2's, this block is not a proportioning block. It's simply a "dumb" distributioning block It's only function is to sense a large pressure difference between the brake lines going to the front wheels and the rear wheels. The blocks are steel with and the holes where the brake lines are screwed into can seen to have little brass "cones" pressed into them. These are the male surfaces that mate to the female surfaces in your brake lines. If this fitting is leaking and continues to leak, the brass cone is scratch/corroded. If you really want to save your distribution block, I do know that Paragon will restore them. I'd guess this means they install new brass cones. Paaragon and In-Line tube sell repro blocks with new cones for about $100. I don't know how much they charge for a restore. BTY, a good used condition distro block for a 68 will sell on ebay for over $200. I might have seen a $300 bid price..don't remember. The original distro blocks have a dimpled/grainy surface. The repros are smooth machined steel.

Nothing personal..general philosophy,.....when you put in new brake lines in a really old car, replace the distro/distribut blocks also. Also, I'd go further and say replace/restore the MC, put in new brake calipers....everything new. With these old cars, you just end up chasing your tail if all you do is just replace obviously failed components.
 
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The junction block in my car appears to be brass. A magnet will stick to the lines, but not on the block itself.

Mine was also, same about the lines....TWO of my steel lines are OEM....

believe it or not.....:amazed:
 
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