71 Cuda Front Drum Brake Question?

Posted By: TimS

71 Cuda Front Drum Brake Question? - 11/18/12 11:02 PM

I've been working on a nagging issue I've had with my 71 Cuda for quite a while. When the brakes are applied hard/quickly I get a pull to the left. I've replaced all springs and had the wheel cyclinder apart. I didn't replace because the cylinder appears to work just fine. The master cyclnder is fairly new but I don't see that being an issue anyhow. I'm beginning to wonder about the proportioning valve. In all my years I've never had an issue with that or ever replaced one. Any ideas/suggestions? Thanks!

Posted By: rth

Re: 71 Cuda Front Drum Brake Question? - 11/18/12 11:43 PM

First make sure brakes adjusted evenly,rears also. Check tire pressure. Wheel bearings adjusted corectly? Next check front end components for wear and play. Tie rods,idler arm, u&l bushings, u&l ball joints and of course strut bar bushings. If all that seems good, make certain strut bar nuts are tight.

Posted By: bonefish

Re: 71 Cuda Front Drum Brake Question? - 11/18/12 11:58 PM

what ever way its pulling,loosen that side up 1 click at atime and see if that fixes it.i had a 71 and it drove me nuts,i could get it perfect for a while then it would start pullin again.It,s got disc on the front now,no more pullin.

Posted By: TimS

Re: 71 Cuda Front Drum Brake Question? - 11/19/12 12:56 AM

Quote:

what ever way its pulling,loosen that side up 1 click at atime and see if that fixes it.i had a 71 and it drove me nuts,i could get it perfect for a while then it would start pullin again.It,s got disc on the front now,no more pullin.

It pulls left and if I take the self adjuster off and loosen the brakes it works but with the adjuster cable hooked up and the brakes adjusted correctly, it pulls left. I have two other cars with the same style manual drums, my 72 Barracuda with 10's works great along with my 68 Bee with 11's. I've redone those without any issues. These Cuda 11's should be the same.

The front end components are good. It's definately a brake system issue. They also work pretty well if you push once then let off and hit hard. They go straight then. It's more of a panic stop when they pull allot.

Posted By: RapidRobert

Re: 71 Cuda Front Drum Brake Question? - 11/19/12 03:57 AM

Quote:

It pulls left

the right side ain't doing it's job & very likely the RF rather than the RR. I would give the RF a good visual: shoe/drum clearance, smooth contact pads (6), partly collapsed hose, linkage issue, wheel cyl issue

Posted By: TimS

Re: 71 Cuda Front Drum Brake Question - 11/19/12 03:12 PM

Quote:

Quote:

It pulls left

the right side ain't doing it's job & very likely the RF rather than the RR. I would give the RF a good visual: shoe/drum clearance, smooth contact pads (6), partly collapsed hose, linkage issue, wheel cyl issue

That sounds like a good idea. I've looked at that side before but plan to hit it again. I know the wheel cylinder is good but maybe something is impeding fluid flow. If I don't find anything i plan to check out the proportioning valve. Finding no issues with the left as far as shoe return, the right must not be as responsive brake to drum contact as the left.

Posted By: RapidRobert

Re: 71 Cuda Front Drum Brake Question - 11/19/12 03:35 PM

I'd jack the front wheels off of the ground & adj each side to where there's a slight "tick" of contact during 1 point in the tires' revolution as you hand spin it forward. It may take several trips down the road/several adjustments to get em dead even & the shoes need to contact the drum at pretty much the same time on each side & 1 side slightly looser will give your symptoms. Holler how things turn out

Posted By: TimS

Re: 71 Cuda Front Drum Brake Question - 11/19/12 10:34 PM

Quote:

I'd jack the front wheels off of the ground & adj each side to where there's a slight "tick" of contact during 1 point in the tires' revolution as you hand spin it forward. It may take several trips down the road/several adjustments to get em dead even & the shoes need to contact the drum at pretty much the same time on each side & 1 side slightly looser will give your symptoms. Holler how things turn out

I got em even but it still panic pulls to the left. I've taken the shoes off again and checked to make sure the wheel cylinders are nice and free. I actually manually adjusted the lefts so they are not even close to the drum and it will still pull left once contact is made. I'm still thinking proportioning valve. Lines are not kinked and like I said earlier can't see how the master cylinder would be at fault though it is fairly new. Not loosing any fluid anywhere to make the rights sluggish and give under pressure. Pedal is nice and solid.

Posted By: RapidRobert

Re: 71 Cuda Front Drum Brake Question - 11/20/12 12:34 AM

The single line to the fronts T's downstream from the prop valve/splitter so each side recieves the same psi even if the prop valve is malfunctioning though there could be a partial blockage on either the LF or RF usually in the hose. This is a tough one. Holler how it goes.

Posted By: AARCONV

Re: 71 Cuda Front Drum Brake Question - 11/20/12 12:42 AM

look for a out of round drum

Posted By: TimS

Re: 71 Cuda Front Drum Brake Question - 11/20/12 12:44 PM

Quote:

The single line to the fronts T's downstream from the prop valve/splitter so each side recieves the same psi even if the prop valve is malfunctioning though there could be a partial blockage on either the LF or RF usually in the hose. This is a tough one. Holler how it goes.

Both the front lines go directly to the proportioning valve on my car. Should there be something else in between somewhere?

Posted By: RapidRobert

Re: 71 Cuda Front Drum Brake Question - 11/20/12 02:26 PM

Quote:

Both the front lines go directly to the proportioning valve on my car. Should there be something else in between somewhere?

No, my mistake on that. EDIT yes it might be the prop valve. That might be a plan to take it off & blow it out or if it'll come apart to a certain extent then blow it out.

Posted By: 70mopes

Re: 71 Cuda Front Drum Brake Question - 11/20/12 04:10 PM

Replace both front brake hoses... regardless of age or apparent external condition. That fixed the same problem I had on a '70 'cuda with 11" manual drum brakes.

Posted By: TimS

Re: 71 Cuda Front Drum Brake Question - 11/20/12 06:16 PM

I think both are good suggestions. I plan to remove the lines from the front one side at a time and work my way back to the proportioning valve then master cylinder. There has to be some blockage somewhere in the lines or the valve.

Posted By: TimS

Re: 71 Cuda Front Drum Brake Question - 12/03/12 03:58 PM

Quote:

Replace both front brake hoses... regardless of age or apparent external condition. That fixed the same problem I had on a '70 'cuda with 11" manual drum brakes.

Bingo! That fixed my issue with this 71 Cuda. The RH brake hose is partially plugged with something, or may even be coming apart internally. They are the originals so I replaced both.

Posted By: TheRamMan

Re: 71 Cuda Front Drum Brake Question - 12/05/12 03:11 AM

the gent above seems very hot....... check the DRUMS very well
TRM