Hi all, I am trying to use speedway drums with some juice brakes. The fronts are fine. The rears spin free until I tighten up the wheels and then the wheel locks up. I have turned the drums to true them up and it helped a little. I can see some rubbing marks on the brake pads and have sanded them down a little. I’m afraid if I turn the drums more I will ruin them. The drums slide over the rear wheel hub. Any thought on what is going on?
Are you certain you have the correct drums and the correct brake shoes? Sounds to me the brake shoes are too wide for the drums, to test this put some chalk on the outside edges of the brake shoes (not the faces, the edges) put on the drums, then spin the drums while pushing them towards the backing plates. Post what you find out.
Brakes are going to have some drag if they are adjusted right and correctly adjusting brakes means that you tighten them up until the wheel won't turn and then back the adjustment off until you get the right setting. Now after seeing Junkman8888's post I have to ask and we need to know what brakes are you working on. What drums as in part number and what shoes as in part number along with what backing plates. There are certain issues to deal with on some of these brakes that need to be taken care of for them to work right.
Trouble shoot problem by removing the brake shoes, reinstall drums, tighten wheel lug nuts. Maybe the drums are locking up against the backing plates?
If tightening the wheels makes the brakes lock, then either the drums are hitting the backing plate, or they are contacting the shoes. At any rate you should be able to see some witness marks. If you don't see any, I would tighten the wheel until it locks up then loosen them just a bit until you can turn them. That should give you some witness marks.
You didn't by chance put the shoes on the wrong end of the car? A lot of drum brake cars have the same diamter shoe front and rear but the rear is a bit narrower than the front. Rears will work ok on the front as they just don't contact as much drum surface but the fronts will be too wide for the rears. Also if you are working on a rear end from a mid 70's or earlier Ford they often had more than one rear shoe and or drum width for the same model of Ford with a different engine trans combo. You have to know exactly what you are working with original application wise to get the right combination.
Here are some pics. The shoes stick out about 1 1/2” and the drums are 2” deep. It looks like it’s hitting the pads at the top. I already had the drums turned 2 times. They slide on easy.
Tighten the wheel only “a little bit” to see if you can get them to drag just before they lock up. Maybe only use two lug nuts. If you can get it to drag, spin the wheel a bunch then remove it all to see if there are any witness marks on the drum or backing plate, or anywhere else.
Backing plate off center with the axle ? Loosen the backing plate hardware and see what happens. Might need to jostle it around on it's bolts a little. Mike
Looking at yours and looking at a tired loaded 40 backing plate I have it looks like your shoes are riding a bit high on the backing plate. I took a photo of the pages in my 1946 Motor manual that tell how to adjust them but one page may not be too readable. View attachment 5632127
You haven’t told us what the brakes are off of, but, there are two sets of adjusters on early Ford backing plates. One adjustment sets how close the shoe is to the drum via a stepped cam, but the more important adjustment centers the shoe on the drum. If that adjustment is off, the drum will slide on, but the shoes will hit on the top or bottom of the shoe. You have to start with correct adjustment FIRST, before you remove any more brake drum diameter.
As badshifter mentioned above if you have the early style the lower cams must be adjusted first before the upper cam...do you have the early backing plates ? Photo I downloaded so credit to OP..
The normal starting point for that style Lockheed brakes is with the little dots on the lower anchors are facing each. You could also clamp a wire onto the hub and rotate it and see how concentric the heel, toe, and center point of the shoes are to the hub. There are some bad repop shoes; but if I remember right they put the shoes too low; but I would compare the new shoes with the old ones to be sure there isn't a new variant out there.
Or, if it’s a 48 backing plate it won’t have the adjusters on the bottom. Can’t tell from the pics, and sounds like the OP isn’t really sure of what he has. To find points of interference, sprinkle talcum powder on everything and then assemble. Then pull the drum off and check for rub spots.
Have you checked the hub for run out? Maybe it's pulling the drum out of shape when you tighten the wheel.
I've had trouble with the repro (MT) drums rubbing on the backing plate. I've had luck with having the back side of the drum turned off of the width about a 1/8" or using axle shims to bring the drum out a bit. Works for me and it sounds like when you tight your bolts, it's moving the drum in a little bit. I've also found that the casting and machine work on these drums is not consistent. My cure works for all the Ford and Merc brakes from '39 to '48.
Thanks everyone for the response. I have the older style backing plates. I’m not sure what they were off of as this was all pieced together. From what I can tell it’s not rubbing on the back plate but it is rubbing on the tops of the shoes on both sides.
I have the lower adjusters and the upper ones set as you suggested. The shoes are all of the way in. It appears that the shoes are riding high.
you have 39-41 Ford brakes. for crying out loud do not cut your drums again, the eccentics raise and lower the shoes. It is a somewhat complicated process . here is how you do it ************* ADJUSTING BRAKES ************** ADJUSTING ANCHORS ON ’39-‘41 FORD/MERC BRAKES: These are Ford Lockheed (not Bendix) brakes and use special brass washers in conjunction with eccentric anchor bolts to position the shoe. The top of the shoes are controlled by eccentric cams. The anchor bolts at the bottom of the backing plate control the shoe position by rotating eccentric washers at the bottom of the shoes. Before starting to adjust, verify all anchor bolts turn freely. The ’39-‘4 use anchor bolts which have locating marks (either a dot or an arrow for position reference) indented on the elongated ¼” head of the bottom adjusting bolt. These anchor bolts extend through the backing plates from the drum side and are adjusted externally after loosening their large external lock nuts. After adjusting the shoes, the adjustor lock nuts are tightened without permitting rotation of the anchor pin adjusters. (1) Always rotate the wheel in the same direction the wheel turns as when the car moves forward. (2) Begin by backing all the way off, the two 11/16” eccentric adjusters at the top of the backing plate until the wheel turns freely. Then slightly loosening both bottom anchor bolt lock nuts (3/4”) on the back of on backing plate. Turn all of the two elongated locator marks (either an arrow or a dot) on the 1/4" adjusters so they face each other. (3) Further adjustments are made by turning the anchor bolt adjusters in a SPECIFIC direction..... (a) Driver’s side. The front shoe anchor ¼” adjuster bolts (with the dot or arrow) on the both the front and rear wheels are rotated counter-clockwise when looking at the back of the backing plate. The rear shoe anchor ¼” adjuster bolts (with the dot or arrow) on both the front and rear wheels are rotated clockwise. This is VERY important. (b) Passenger side. The front shoe anchor ¼” adjuster bolts (with the dot or arrow) on both the front and rear wheels are rotated clockwise when looking at the back of the backing plate. The rear shoe anchor ¼” adjuster bolts (with the dot or arrow) on both the front and rear wheels are rotated counter-clockwise. This is VERY important. (4) Now turn one of the upper adjusting 11/16" eccentric cams until the wheel cannot be turned. Adjust its 1/4" anchor bolt in the correct direction until the wheel just does turn. This lowers the shoe and moves the toe of the shoe away from the drum, which will result in fuller shoe contact. (5) Repeat step (4) over and over on the same shoe until turning the anchor bolt will not free-up the wheel. (6) Back off the upper anchor pin very slightly until the wheel will just barely turn. Tighten the anchor pin lock nut (3/4”) and then adjust to the other shoe on that wheel. (7) Thereafter, it’s common to never needing to adjust anything other than the top eccentric cam. TIP: If you’re installing new shoes, which have been arc-ground to fit the drum, you normally will not have to go through the preceding exercise. Turn the dots/arrows until they’re facing towards each other and tighten the ¾” anchor pin nuts. This correctly positions the brake shoes and you don’t have to go through the anchor pin adjusting..... just adjust the upper 11/16" cam adjusters. ADJUSTING ’42-’48 BRAKES: The anchor pins are different than the ‘39- ’41 Lockheed brakes, but do not have any reference marks on the backside of the anchor bolts. And they adjust differently. Instead they have one flat side ground on their large round shallow bolt heads. The flat sides are turned so they face each other. This is usually al the adjustment needed due to the semi-floating design of the anchors. Tighten the large nuts (which are on the inside of the brake drum)and put on the brake drum. Adjust the upper eccentric cams and you’re through.
Take a look at the “seating ring” on the back of your wheels, and see where they contact the brake drums. If the wheel is pushing on the brake drum outside of the axle flange it will bend the brake drum inward against the brake shoes.
Make sure the drums are not hanging up on the lug studs where the studs are bigger than the threaded part.
Update I followed Moriaritys procedure and it helped. With the bottom adjustments lowering the shoes as far as it will go and the tops all the way in the drums spin with a slight drag. The tops of the shoes rub just a little. I am fine tuning the brakes next. want to thank everyone for their help and support. THANK YOU!
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