Brake bleeding question

JPhil

Huh?
Joined
Mar 26, 2008
Messages
1,361
Location
Loveland, Colorado, USA
Just got done replacing the front hard lines. I did not replace the hard lines from the master cylinder to the distribution block, or any of the hard lines to the back end. Did not replace the flex hoses to the wheels, they are VBP rubber lines about 8 years old, as are the calipers and the rear flex & t-arm lines.

Getting ready to bleed it now, but it occurred to me: Do I need to bleed the back wheels as well? My distribution block has the 'brake balance switch' (or whatever it's called) which shows a light on the dash if one side loses pressure compared to the other. To the best of my knowledge it is not a front/rear proportioning distribution block, only has the dash "brake" light switch (which is also the e-brake light).

It is a vertical block. Rear MC line comes in the upper side and out the top to the rear end. Front MC line comes in on the lower side, the driver side wheel line comes out opposite it on the lower side and the passenger side wheel line comes out on the very bottom. The switch is in the middle between the two halves.

Will the air now in the lower (front) side of the block get into the upper (rear) side of the block through the switch?

The car has always an intermittent pull to one side when I hit the brakes after a while of cruising. That is, when I use them often as in traffic, it stops straight and true. But when I cruise for a while, sometimes the first time I press on them it pulls. And what is interesting too is I can't remember if it pulls always to one side or the other. I know it pulls to the left, but I think sometimes it's also to the right. It's odd enough that I can't necessarily prepare for it, I just have to be ready to react whichever way it goes, if it does. Hopefully this fixes it.

It's going to be a couple months or so before I can find out if replacing these two lines fixed it, I just took all my engine parts into the shop this morning for my stroker build.
 
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My '72 had that same damn switch thing, and for some damn stupid reason it would let AIR INTO THE LINES, I fought that bastard tooth and nail for a long time, replacing shit, rebuilding the stainless calipers the car came with, playing with runout, seals, pistons, springs, whole 9 yards, and even before the Hydroboost install which gave me a good steady pedal, that lousy POS freeking, EFFING brake light switch for some stupid reason would allow air into the REAR calipers....I finally just said hell with it, put a line splitter in it's place for the front, same as back brakes.....and ran the lines direct to the master.....one front, one rear, and it never gave me another air in line problem since and it's been YEARS......

but the pedal feel problems were solved with HB....vacuum sux....

course I have had this car for 20 years now, it goes to my son when I kick off.....he a pretty good wrench, having put an LS engine into a '57 chebby pickup....project underway.....BUT up and running.....even got disc brakes on it, and HB of course....the truck belonged to his wife's father.....:yahoo:
 
"For closure"

I did not re-bleed the rears, I just pressure bled the fronts, and there was no problem with any air into the rears. Brakes work fine, and so far no more pulling to one side or the other.
 
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