I had an unpleasant day today and had to get on the brakes pretty hard. The darn thing easily locked up the rear brakes, but the front weren't doing much stopping. It felt like I was doing more steering than stopping. She went sideways, I let off the brakes to straighten out, ...rinse and repeat. This is a build that I bought and has a bunch of miss-matched parts. It has a GM drop-out rear end, and an aftermarket straight front axle. I don't know what brakes it has, other than being drum on all 4 corners and the original single reservoir master cyl. Is there a device I can add to adjust the front/rear balance? Or is there a better way to manage the pressures.
So.....I got this black car see, and at stoplights it runs perfect...........can you tell me what kind of car it is? You have to provide as much info as you can, type of car, pics would help.....pretty vague stuff in your post, be more specific.
Well, I was hoping to get some general info on brakes, without being shunned for having something different. In this case, the "black car" I am working with is a '52 Studebaker truck. The brake master cylinder is original type, and only the "everything else" has been changed. I'm not sure if my issue is a weight bias thing, or if my rear brakes are larger than the fronts...or both, but it feels like I have good brakes until I want to be a bit more serious than simply slowing down. I'm looking for a way to get more stopping power from my front brakes without the rears locking up. Honestly, it felt as if I was on a wet road or ice. The rears were locked and squealing, and the truck was going sideways, but it wasn't doing much slowing down. The sideways pitch turned out to be to my advantage as I came to a stop alongside the car I was trying to avoid. Sadly, I had crossed the center line and was in the opposing lane. Yesterday when I typed out my question, I was still recovering from the adrenaline rush. Today is a new day, and with fresh underwear, I am ready to sort out the issue and find a solution. Until then she will remain parked.
Definitely going to need some additional detail on this one. Measure the drums - diameter and depth - same front and rear? Assuming only one exit port on the master - is the line to your front brakes pinched? How's the adjustment on your front brakes, or the rear for that matter? I like mine to just barely drag when spun on a jack. You can put a proportioning valve in, but I think that would be more a crutch than a fix. Mike
Tangent question: when were load-adjusting proportioning valves first used on pickup trucks? It seems that locking the rear brakes on an empty truck has been a problem for a long time. My fwd hatchback DD has such a device operated by the rear torsion beam. I think the position on the beam was changed during the production run, because an earlier one I had could be coaxed into locking the left rear only – handy for certain moves but tricky in inexperienced hands.
With the rear axle (and brake) swap a proportioning valve might be required to adjust the front to rear brake bias. But before even thinking about that get the drums off all four corners and do a close inspection of the shoes, drums, springs, park brake linkages and cables, wheel cylinders, etc. Look for grease, oil, gear lube and brake fluid leaks leaks that may have contaminated the shoes. Without the brakes being in sound mechanical condition it's going to be difficult to troubleshoot. And as already mentioned, on an older P/U with no load in the bed the rear brakes can be a bit skittish by nature. Post some pics of the brakes so we have a better idea of just what we're dealing with.
I took a look, and they are the same on all 4 corners: 11x2" and the wheel cylinders are all the same. I have not done any cleaning, this is how they looked when the drums came off. Everything looks new and dry, and the drums look as if they are new or recently turned. The adjustment was ok.. Pretty hard to rotate by hand on the drums, but feels more like a slight drag when the tires are on. Is this a Chevrolet style brake? The only difference I noticed was the brake linings. The fronts look to be a grey color, while the rears look like they are a bit reddish in color. I did a close inspection of the brake lines, and no kinks or pinches anywhere. I suppose the flex lines could have an internal issue, but from the outside everything looks to be fine. It looks as if we've narrowed it down to being a weight bias issue..The rear end is just too light. Now how can i adjust the brake pressures to prevent the rears from locking? This truck will never see a load in the back.
The brakes are Bendix design and normally found on Fords. The front wheel cylinders should be larger internally than the rears, so take the time to actually measure all of them. Odd why the front and rear linings are different, but the same width. I would think about replacing them with matching linings. An adjustable proportioning valve may be needed to reduce rear braking and prevent rear slide. But first make sure the front wheel cylinders are larger than the rears. You don't want to limit rear braking when the front brakes are not doing their share.
Had a similar problem years ago with a '58 Ford 1/2t with a hemi/auto. Stock brakes, 11x2. Fixed it by swapping the fronts to 12x2.5 from the same Chrysler that donated the hemi. Took a little modification, but worked great. My thought was adding braking to the front vs reducing pressure to the rear would be a good thing.
Bendix brakes are 'servo type'. The forward shoe begins the stopping process by engaging the rearward shoe to do the stopping, as it ends up at the pin. (rigid point) The rear shoe has the longer lining, on a Bendix brake they are never 'matched'. (brake school 101, 1957)
"servo type"...I always knew them as "self energizing". This action is why a manual drum takes less pedal effort than a manual disc. V8 Bob has a good point; the wheel cylinders may look the same from the outside, but have a different bore size. I will check that out. And I agree that adding more braking to the front is better than reducing braking to the rears. Geez, I need to find a parts house that uses books instead of a darn computer. (pictures self telling parts guy "I need a set of brake shoes like this" [places shoes on counter] Parts guy: "year, make and model?") Grrr. Once I had a parts guy tell me "Oh, those old Studebakers were nice trucks...who built those?"
Self adjusting parts may solve your problem since all 4 wheels will adjust properly. You can get all the small parts needed. Yep. Front cylinders Are supposed to be larger.
Servo acting brakes are one shoe applying the other, self energizing refers to the shoe being able to be wrapped into the drum, servo brakes are self energizing and some leading trailing brakes are as well Sent from my iPhone using H.A.M.B.
Servo acting brakes are one shoe applying the other, self energizing refers to the shoe being able to be wrapped into the drum, servo brakes are self energizing and some leading trailing brakes are as well Sent from my iPhone using H.A.M.B.
Wilwood offers an adjustable proportioning valve. Or go to Amazon, they have a bunch of options to choose from and it can be delivered the next day. Amazing
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