I've got 4 wheel drums and it stops very straight almost all the time. But sometimes it heads for the ditch. I've been told is the rubber brake lines in the front. They seem to be very old and should be replaced, but there must be another problem. That's not logical.

Well, if the flex hoses "seem very old" (I'm guessing this means visible cracks and other deterioration) then yes, they should be replaced soon (if not sooner). Usually, they will not cause a pull, though. Drum brakes tend to pull because they're not adjusted the same side-to-side at the front or the rear, because there's contamination on one side but not the other, because one got wet and the other did not, because it's Tuesday, etc. As frustrating as it can be, sometimes the pull is intermittent. How long since the brakes themselves have been inspected and rebuilt?

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一期一会
Too many people who were born on third base actually believe they've hit a triple.

I've never looked at them. Yes I should and soon. I've been busy and its not a daily driver. Not a very good excuse. The last car show I attended I mentioned this intermittent pulling. The group of "experts" attending said it is most likly the hoses rotting from the inside causing a check valve type action, even though the hoses from the outside look old but decent.

The "check valve effect" explanation is possible, but probably not what's going on.

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一期一会
Too many people who were born on third base actually believe they've hit a triple.

Its happened to me when I still had my '70 Fury. A change of both front hoses fixed it (don't do just one).

i took my 70 valiant with drums to Midas.

it's hard to find a good shop without any crackheads or young guys that acutally know what drum brakes are.

charged me $450 for full rebuild. New shoes, drums, bearings, master cylinder "bench rebuild", and adjustement.

car stops great, doesn't pull, and it seems to be driving straighter than before..


my 2 cents

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70 Plymouth Valiant 4dr

Sounds like you had a good experience, which means you got very lucky. Midas is always a large gamble!

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一期一会
Too many people who were born on third base actually believe they've hit a triple.

I had the magic Check Valve hose effect happen to me On the Front discs on my volare.

It would pull on a sudden stop - took me the longest time to find out what it was.


I replaced pads, calipers, Then I replaced hoses - I could not even blow air thru it because it was so clogged with crap.


Greg

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http://www.youtube.com/hyperpack

It's a little off the topic, but I've seen the same sort of thing happen in an exhaust pipe. As I recall it was a 65 Mercury. The car was towed into the shop because it couldn't generate enough power to pull itself even though the engine would start and run. After days of daignosing and head scratching the guy who was working on the car decided to check the exhaust pipe. The pipe was a double walled tube and the inner wall had rusted and collapsed, closing off the pipe.

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David Kight
'62 Valiant Signet, White
'98 Dodge Dakota
'06 Jeep Liberty

Growing older is unavoidable but growing up is strictly optional.

This is a remote possibility with a Mopar, but it DOES happen. Check your ride height, and check your LCA front strut bushings. If the ride height is low, and one control arm hits the stop when you brake, it will pull that way. In the same way, if the LCA strut bushings are bad, play in one will make that side not stop as efficiently. All the other stuff said is true too. If you can't remember when you replaced the flex lines, they are probably too old. I would spring for stainless if you can find them. They are not that much more expensive, and work better.

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What happens if you do repeated stops?

If it starts to consistently pull after repeated stops, the self adjusters aren't equal side to side. (one side is rubbing heating up the shoes more which causes the pull)

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Ed
64 Valiant 225 / 904 / 42:1 manual steering / 9" drum brakes

its completly random.

Just peek under the car at rest on level ground and see if the bump stops are closer on one side then the other on the lower control arm. If one is real close, then it will touch first when the nose dips down as you first apply the brakes. I have seen many of these cars where both sides are bottomed out. You will not get a car in this condition to stop straight. The side that touches first will make it pull in that direction. Just lubricate the adjuster bolts, and crank up on them with a 3/4" socket and long breaker bar, until you have a decent amount of space there. The shop manuals are very specific about where to set the ride height, but I have found that you can play around with this, and decide for yourself how you like it to handle.

Check you rear leaf springs. If one of them has a broken leaf, or weak leaf, it will do the same thing. If the right rear spring is weak, and the car sags on the right rear, this will lift the left front, and leave the right front close to the bump stops. I think I have got that right. If not, someone will correct me here I am sure. Anyway, the point is, the condition of yoru suspension is just as important to straight stops as the condition of your brakes.

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