Dtimekw

Hey guys and gals, new to the board and Mustangs in general. I bought my son (16, first car) a 66 coupe with 289, C4 and drums all around. Right after buying it, we blocked it and pulled the motor/trans. for other reasons. While they were out, we upgraded the brakes with a power booster and dual bowl. We connected the rear brake line to the rear bowl and the front brake line to the front bowl. From the bowl, we ran a single hard line to a TEE which split off to each wheel. We have replaced the wheel cylinders, shoes, springs and star adjusters. The drums do not look chewed up or have grooves. We have not replaced them however. I've had the car aligned and replaced all the front end with poly bushings. I can't say for sure if when the car started pulling since we didn't drive it much before doing all the work. I've tried adjusting the front/pass brake tighter and seemed to make things worse. I've also loosened both front brakes and performed the self adjusting (back up and hit brakes several times) This just takes the brakes right back to the car pulling hard left. It is at the point now that the front/driver wheel locks up under hard braking and the front/pass does not.

What am I missing?? Any help would be appreciated. I know my son would too since he is not happy about walking to school

Gun Jam

If your running a dual master cylinder im 99.9% sure the small reservoir in the front goes to the rear brakes and the larger rear reservoir goes to the front brakes. so check into that. If both reservoirs are the same size its fine but if one is larger make sure it goes to the FRONT brakes.

Next it sounds like you may have air in one, several or all of the slave cylinders causing an unequal brake bias thus causing the car to pull. I would attempt to bleed the system again...what method did you previously use to bleed the system?

-Gun

Dtimekw

Gun,

Thanks for the reply. Both bowl sizes are the same. I read the same thing but was told by the manufacturer of the upgrade that the front bowl goes to the front and rear bowl to the rear.

As for bleeding, we have bled these things to death. We used both a vacuum pulled from the bottom and the old fashion way of "pump the brakes and open the bleeder". Since posting, I've swapped drums with no luck. There is no grease/oil on the shoes or drums. I've considered bump steer but really don't think that could be it.

I went back and loosened both brake adjusters. When I first apply braking, it does not pull to the left very much but once I do the self adjusting (backing up and applying brakes several times) it goes right back to pulling hard left under braking. I can't think of anything else but the driver's side is braking with more force than the pass side which would be:
(1) a lazy wheel cyl on pass side (which was replaced, no joy)
(2) air in the lines (bled and bled, found air but after 5 good bleeds with no air, we stopped and called it good).
(3)greasy/oil/worn shoes (replaced with no joy)

I know this is something simple but dang, it is kickin' my butt!

JDraper

I agree with Gun Jam...try re-bleeding the brakes. Order should be right rear, left rear, right front, left front.

I'd also make sure you have the brake shoes on correctly. If you swap the front and rear shoe on a given wheel, it can cause braking problems.

oops..looks like we posted at about the same time....

It might be possible that one of the adjusters is damaged or in wrong...

Gun Jam

are you running a proportioning valve by chance?

and the shoes are ALL new? or just one of them?

-Gun

Dtimekw

New shoes on all 4, new wheel cyl on all 4 and new adjusters on front. I thought of the shoes being improperly installed. I am pulling both sides right now just to be sure. The shorter shoe lining goes to the front, correct?

I am not running a proportioning valve, just a tee for the front brakes.

Gun Jam

after you check the shoes and put the drums back on feel by hand to verify if there is equal resistance on each wheel...do it with the car on jack stands and have someone apply brakes while you rotate each drum or wheel assembly and see if the opposing side stops at the same time or if one keeps rotating longer. at 0% brake there should be slight resistance and you should hear the pads brush against the drums

....It's starting to sound like maybe it could be a suspension component you replaced the busings but what about the ball joints, tie-rods (all the crap with ball/sockets at the end)?

-Gun

Dtimekw

I just checked the shoes on the front. The smaller liner is toward the front on both sides.

Can the rear brakes jerk the steering wheel dang near out of your hand when you apply the brakes? I am at a loss here. We are putting the car back up on all 4s and will bleed all four wheels again tomorrow.

What am I missing!!!!

This is driving me to drink.....

Gun Jam

the car has no power steering? and when you apply the brakes it pulls so violently that its difficult to hold onto the steering wheel???

Why do you blame the rear brakes....and no bad rear brakes shouldnt cause it to yank the wheel from your hands

when you bleed the brakes do you get even amounts of fluid from each cylinder?

Gun Jam

try this....with the car on the ground all the wheels on of course grab a tire from the tread with both hands (one had at 3 oclock and the other at 9 oc) and yank it towards you like you wanted to rip it off the car and chuck it then rapidly push back in on it do this rapidly a few times...do you hear any clanks or feel any play in the system or is it very solid minus the car its self rocking back and forth?

try it on both fronts...do they feel the same pay close attention.

-Gun