anyone had ever issues with prop.valve

[lilredridinghoo]

hi - just messing around, with a mystery problem concerning my frontbrakes

10 inch front drums and rear drums on a dual-mastercylinder

i´d change everything inside the drums, in the meantime, know the last part would be the prop.valve

my problem:

if the car is cold - no issues

if i go for a ride on the motorway and the engine bay heats up - the car starts to drag to the left side.

if it sits for a while and will cool down, no problems - no dragging,
if it heats up or if it´s been driven for a while the issue comes back.

in the summermonth (June till end of August) it was much more quick to notice than now in Oct.

i´d talked to an Ford-Mustang Guy and he told me had similar issues - and have chucked the prop.valve replaced it with a T-fitting for the front brakes and an adjustable valve for the reardrums.

what do you think about a miss-working prop-valve

and the replacement option

 

[VDART]

if your car is 4 wheel drum-- then the junction block you have is a "T" fitting -- Proportioning valves were used on front disc/rear drum cars.

Have you replaced the rubber lines going to your front brakes? If they are old the rubber detoriates & the brakes are not as effective.

When you stop cold does the car pull a little to one side?
Lawrence

 

[daredevil]

Is the dragging when the brakes are applied? Could headers be heating right side hose as to render the right brake ineffective. Did car sit maybe, proportioning valve stuck. Not sure but believe it only propotions front to rear. I has a similar problem and slammed the brakes and observed the skid marks.One wasn't locking up like other three. Changed hose to caliper and it corrected it. Hose was weak and swelling when applied.

 

[dgc333]

On drum brake cars there is a residue valve in the master cylinder that keeps a couple of psi of pressure in lines and wheel cylinders to prevent air from be sucked in past the seals. I had a similar issue once where these valves were getting plug up with gunk and after several applications of the brakes they would drag and it would take awaile for them to blled back down.

Also, as Vdart stated the drum brake cars do not have a proportioning valve, it's just a distibution block with a switch between the front an back to trip the warning light if one side fails.

 

[lilredridinghoo]

thanks for the prompt answers.

@vdart - the hoses were replaced about 3 years ago.

when stopping cold i have no issues no pulling even left or right

if i understand it the right way - this block (looking like a puzzle-part) doesn´t really regulate some it´s only a block with some holes dividing left and right


hmm looks that i also have to replace the master and the hoses