I’ve recently fitted the boling brothers Lincoln/bendix brakes to the front of my 41 ford. The brakes work fine, but if braking hard the lower outer edge of the leading shoe contacts the mounting face of the drum causing a horrible metal to metal screech. Circled in red 925D50D9-1943-4C1A-AD24-A1C3ADBBBF13 by KFC posted Aug 25, 2019 at 11:56 AM I had used the drums with 1” 3/4” brakes previously but I had them checked for wear and they are fine. I’ve been over the brakes several times they are assembled and adjusted exactly as per the instructions and they work well. I’ve swapped the shoes side to side etc. Makes no difference. I’ve emailed boling brothers but got no response It’s driving me mad, has anyone else suffered this and solved it.
I’ve seen this once with drums that where machines on a bad lathe. Even though you could not see them or really even feel them the lathe had cut threads into the drum and in braking would wind the shoe into the drum and make noise. Maybe ?
Dunno....backing plate flat? Could be the drum pulling the shoe out as Vandenplas described. Have you tried swapping the drum to see if it happens on the other side?
Early '60s, a MoPar rep came to our shop, (in response to some complaints by customers regarding 'break squeak, shudder, etc.) The MoPar Lockheed style brakes were 'sensitive' to excessive heat, wear, et al over miles covered... The rep had a 'kit' he applied to a '59 Chrysler on our hoist. The 'anvil tool' attached to a sleeve fitted to the front spindle. Its 'pointer' arced around the backing plate (stripped of shoes/hardware) and indicated a difference in height of .040" in the different 'blocks' on the backing plate. A 2 lb. ball peen hammer raised the 'blocks' as the backing plate was 'tapped' level. Then, shoes were carefully arced to freshly turned drums. Result after careful adjustments? No more 'shudder' no more squeak. Point being, the level of backing plate remaining perpendicular to the spindle stub is critical. I DID like @VANDENPLAS' remarks on the bad drum lathe! (never saw or heard of that one before...)
Every brake lathe will turn threads into the drum, if you think about how it feeds, put a non directional finish on the drum using sandpaper, should be standard practice on drums and rotors Sent from my iPhone using H.A.M.B.
I had the same problem but backing plates were '40 Fords modified to hold chev station wagon guts. The backing plates were warped like .060 when measured to the pads where the shoes rest so the shoes were sitting crooked. Took some work to get the backing plates straight but corrected problem. I made the tool below to check the shoes were square to the drum and also centered. Worked great
They are there just don’t quite show. The brakes are new from boling brothers. The drums have a few thousand miles on them if that and measure at less than .2mm wear I am going to try something similar, the back plates are brand new though but it does it both sides. I work on bentleys for a living and they have a similar problem if the fork from the slave to the shoe is cracked through.
I did just he shoe with a grinder to relieve it but it moved the contact up, I don’t know if I should just cut away the are that isn’t actually supporting the lining
Everyone checks drums for diameter and out-of-round, but I wonder if a bit of taper might cause a condition like this. If the inboard side of the of the wear surface was slightly smaller than the outboard (flange face) surface, applying the brakes might tend to "squeeze" the shoes and force them slightly away from the backing plates. I'm kind of grabbing at straws here, but it would be fairly easy and free to check.
I am going to toss this out there, as just an observation from years past. A friend had a '72 Gremlin, that had wider brakes on the front than on the rear. The difference was all in the shoes, as the front shoes were offset instead of having the wheel cylinder make contact in the center. The result was warped shoes, that would wear out the drums pretty quickly, giving them a large taper, but in that instance, it was tapered down going outward instead of inward.
Your 'anchor' bolt is upside down. The anchor bolt is at the top and it is cam shaped, if you flip it over it'll raise the brakeshoe mounting up (right now it is down), the other visual clue is the pins from the master cylinder and going downhill, they'll be level when you flip the anchor over. When you take it back out look closely at it and you'll see what I mean.
The upper anchor bolt is supposed to be adjustable. Get it kinda snug, but moveable, then put the drum on and press the pedal. Should allow you to wiggle the anchor a bit while the shoes are in their best up-down location. Then tighten the anchor when it's centered. Don't know if this is the cause of your problem, but it should be done anyway. Sometimes if a backing plate won't allow the anchor to be slid far enough up or down, you could use a file and elongate the slot in the plate.
That’s how I set it up, locked the brake on the adjuster with the anchor bolt loose. Had my father hold the brake pedal down and tightened the bolt. I didn’t notice that, is that for sure? I will try it thank you.
That’s what I checked as I’d run 1 3/4 shoes in them. But they checked out fine the .2mm wear was in the centre area.
I shouldn't have said 'cam shaped', its an offset really. Not all are, judging by how the wheelcylinder push rods are angled I'd say the anchor bolt is concentric and upside down. How does the steel web of the brake lining match up to the pads stamped into the backing plate, I'd bet they are below or at the very edge down where you drew the circle.
This is what we did to hillbilly re arc the shoes to the drums on the Boling brother lincoln brakes. The arc was close to a match but both ends were off a little. Backed the star adjusters right off , some sticky long board sand paper . Put drum back on and attached the wheel and as I felt more ease of turning the wheel I gave the star adjuster another click . Now the radius looks great . The second pic shows uneven witness marks. The last two pics look uneven due to lighting but are even. [
Only a year plus late.. the car got trapped in paint shop hell amongst other irritating problems. Update, I ended up after load of measuring and messing about, fitting a third retaining spring and pin to the lower corner of one shoe on each side. This stopped the grinding but I always felt the brake effort seemed reduced. Today I fitted 1 and 3/4” shoes to see if the braking effort would increase with fully floating shoes again but not grind. The braking is better. The shoes still contact the drum face though. Which means they are walking a 1/4” across the face of the drum. Genuinely wish I’d never bothered fitting them
I wonder if you can get a stronger shoe retainer spring. Also make sure there's nothing on the backing plate causing the shoe to ramp up when it rotates on the backing plate.
Here's the instructions for adjusting Bolling bros.MT Lincoln Brakes. http://www.mtcarproducts.com/Gallery.html Also, make sure you are using the correct length retainer spring pins which hold the shoes in place. The 2 in wide shoes (shown here) require longer pins than the 1 3/4 wide brakes. Make sure longer shoe is on the rear. Here's some photos of the MT Brakes installed on a 1940 Ford using the MT backing plates and drums plus MT brake kit. Run out on MT drums was .004 in. when bolted backwards on axle.
Had a new Dodge van with the rear drums poorly machined. You could see the threads cut into the drums. It made noise coming off the transport. Both rear drums were the same. I wonder how many got out of the factory that way.
The drums have been checked, After a lot of checking, looking and thinking I’m pretty convinced the backing plates are not flat. The lower corner of the rear shoe one side contacts and lower corner of the front shoe contacts the other side, so the same point on both backing plates as they are not handed and are the same pressing. I just need to make up a gauge to prove it.
Check post 7 Another way is to put the backing plates with shoes down on a flat surface and see if they rock. Measure any gap. Think rocking restaurant table. I had the same problem. I made a big lever to bend the plates on the car. I used a strap from a wheel stud and measured to the backing plate. It just took a few minutes to get them flat.
A friend knocked me up a pointer. The back plate was approx .080” out of square/true, a few bashes and it measures up ok after some whacking measuring through these handy holes in the drum I’ve got it to with in .007” The other side is as bad so that’s tomorrow’s job. these are brand new boling brothers brakes.
Funny thing is my 2001 Chevy 3500 truck does the same thing and has discs up front with the biggest drum brakes I ever saw in the rear..