Another Rear Drum Dragging Thread

[62dodge]

Correct! there is/used to be a machine that would sand the friction material, goes back to the 20's/30's if memory serves. I remember watching that show "The Guild"? where they were seriously hung up on a set of linings that were binding on some pre-war antique, so much so that they were contacting the supplier to get the 'Correct' shoes. Of course this was the final leg of some restoration that was years past it's due date so to say (aren't they all?).

None of them restoration experts in the shop had a clue about this old shoe sanding machine.
I kept thinking FFS get out a belt sander and with the right touch your good to go and it's out the door!

(edit) quick search to please the pic-whores!

View attachment 298884

View attachment 298885

The abrasive: sanding vs grinding (not really a grinder IMO)

View attachment 298886

Last I heard that there is a place in Portland Ore. that still trues brake shoes which is a must on the old style shoes, 62 and older. Unless you want your car to pull left or right. When i get close on my 58,62 than i will send the drums and shoes away to have them trued.

 

[rkrochen]

I have only ever seen a couple of those in all my years. I'll bet that they started getting tossed when a couple things happened... First, most cars are using disc brakes and I'll say that a lot of young mechanics don't know anything about drum brakes. Second, it became more cost effective to replace brake drums... No oversize drums, no shoe grinding needed.

But third... Just gotta think about a machine over in the corner that ground asbestos shoes and sprayed a fine dust into the room. Not what I would want around.

I was just in a NAPA store the other day. I asked my buddy that works there if he could check the size of a questionable brake drum I had... He told me that none of the NAPA stores turned drums or rotors any more. He couldn't even tell me a place that did it on a regular basis.

Man this is making me feel old now, I distinctly remember this being done. Looking at the pics I do believe it would be worth taking the shoes off and fitting them into the drum to see how well they fit.

 

[stain]

I will be taking mine apart and checking the shoe fit this week. I will take some pictures. Unfortunately I threw my originals out.
A vendor told me that to run rear disc, I need to upgrade to power brakes. So that plan is on hold.
I turned my own drums myself at work. We don't have a shoe fitment tool, but I have a belt sander that with some finesse I believe will work.

 

[300cruiser]

Hey Cruiser...When we tested the hydraulics, we made sure the shoe was still energized and popped the bleeder. If the pressure releases and the shoe retracts, it's hydraulic. (Just watch the flying fluid...I attached a hose and into a jug).

From your pics, I would replace that rubber hose. It was inexpensive and easy to change...The Dorman seems good. The distribution block for your 300 may have been used on different vehicles and some of these stores aren't aware, so they are not on their compatibility list. My CBody 67 Polara has an identical block to a B body car (Coronet/Belvidere), but the ONLY difference was in the mounting bracket. I bought the "BBody" block, tapped off the bracket of my old and the new and attached the new block to my old bracket. (See Pics).

To see if your block crosses with other models, download your car's parts manual: MyMopar - Mopar Forums & Information - Parts & Accessories Books

Any questions, let me know Cruiser!

View attachment 297872

View attachment 297873

View attachment 297874

Thanks Pauly - I ordered new rubber hose, distribution block, rear lines, and new brake cylinder, not leaving anything to chance. I hope to swap everything this weekend and test.
Before I dig in, is there any science to mounting the d-block on rear end valve or does it just sit on on it? And how tight do you torque the d-block to the rubber flex, I don't see may references in my manual.
Thanks.

 

[300cruiser]

@300cruiser

Has you checked the length of the brake rod going into the master cylinder? If it's too long, it will hold the brakes on slightly. Easiest way to check is to back off the nuts on the MC until it's a little loose and see if the brakes release. There may be a spec shown in the FSM as how far it needs to stick out, but we can figure that out if need be.

@Pauly's67Polara You really need to start your own thread about this. It's too confusing as both have different problems. Perhaps we can get @tallhair to split these up so both of you guys can be helped.

Hi John,
I haven't investigated the master yet since the issue seems isolated to right side only. Working backwards from the right side towards the master, if my current changes don't correct the issue then I will look to the master next. After that...not sure.
Thanks,

 

[300cruiser]

So you know, I was addressing 300cruiser's problem (which seems hydraulic) and not your's (which looks mechanical). Your problem looks to me to be the worn braking plates catching the shoes and not letting them retract. It sounds like you are on the right track to fix that by building those areas back up and grinding them flat.

But, since you mention it, yes, the push rod is adjustable. Download a factory service manual here: MyMopar - Mopar Forums & Information - MyMopar Tools/Reference

Go to page 5-23 and you'll see the measurement.

I also found a video about the subject that may help @300cruiser He also mentions the residual valve possibly (rarely) giving similar issues.



and the rest of his video on diagnosing hydraulics if anyone is interested.

Awesome videos. Thank you!

 

[barnfind]

Did some research on this, could be made from simple stock iron as these seem to bring $$$ on ebay. Ammco 1750 used on 20s dodge / plymouth brakes to dial them in. Nothing on you tube about these that I found, or the truing machine.

 

[stain]

I did not get to remove my brakes this weekend. I was installing a new metering block. I did readjust the brakes, backed them off more than spec, same story.
Here is the thing that is getting me confused. The rear brakes gets super hot yet they are not sticking. The right drum is approaching 380 degrees after 10 miles of 50 MPH driving. The left drum @225. When I go for a test drive I get out to measure the drum tempetures and can easily roll the car in neutral. The brakes are not stuck on. There is no sign of drag or scraping when turning the rear wheels while in the air.
What am I missing?

 

[mr. fix it]

I did not get to remove my brakes this weekend. I was installing a new metering block. I did readjust the brakes, backed them off more than spec, same story.
Here is the thing that is getting me confused. The rear brakes gets super hot yet they are not sticking. The right drum is approaching 380 degrees after 10 miles of 50 MPH driving. The left drum @225. When I go for a test drive I get out to measure the drum tempetures and can easily roll the car in neutral. The brakes are not stuck on. There is no sign of drag or scraping when turning the rear wheels while in the air.
What am I missing?

Have you ever spilled brake fluid or diff oil on the one set of shoes?

I am presuming that all shoes came from the same box right?
Did you confirm that the front shoe is shorter than the rear shoe on each side?
Have you checked the rear steel brake lines for one being pinched?
I recall Mike Madden finding out that he had both secondary shoes on one side & both primary shoes on the other.

 

[1970cat]

brake shoe grinder

 

[rkrochen]

brake shoe grinder
View attachment 300316
View attachment 300317

That is the machine I was talking about!!!
Thanks

 

[stain]

Have you ever spilled brake fluid or diff oil on the one set of shoes?---no

I am presuming that all shoes came from the same box right?----correct
Did you confirm that the front shoe is shorter than the rear shoe on each side?----yes
Have you checked the rear steel brake lines for one being pinched?yes, but wouldn't that keep the brakes on? The car seem to roll easily. Maybe slow to return?
I recall Mike Madden finding out that he had both secondary shoes on one side & both primary shoes on the other.

 

[mr. fix it]

Have you ever spilled brake fluid or diff oil on the one set of shoes?---no

I am presuming that all shoes came from the same box right?----correct
Did you confirm that the front shoe is shorter than the rear shoe on each side?----yes
Have you checked the rear steel brake lines for one being pinched?yes, but wouldn't that keep the brakes on? The car seem to roll easily. Maybe slow to return?
I recall Mike Madden finding out that he had both secondary shoes on one side & both primary shoes on the other.

Thanks for confirming the above.(I know that there's been tons of replies to this trying to help)
The brake line if pinched but not blocked off totally may result in a slow to release shoes. - I know this is now at the point of grasping at straws here which is why I asked about the lines...
Are they original?

 

[mr. fix it]

Also, axle bearing are good as well right?
No side to side slop...

 

[stain]

Also, axle bearing are good as well right?
No side to side slop...

They seem to be . I will double check. They are not making any noise. If the bearing had side play, would I see marks from the drum on the backing plate? Or marks on the drum from the edges of the shoes?

 

[mr. fix it]

They seem to be . I will double check. They are not making any noise. If the bearing had side play, would I see marks from the drum on the backing plate? Or marks on the drum from the edges of the shoes?

It’s hard to say for sure
Right now you should be reviewing everything else that you can think about

 

[300cruiser]

Update: over the weekend I replaced the flex line, axle tee, and rear brake lines...and no improvement.
Next step is replacing the Master. Looking at all options, I came across a thread about the Hydraulic Safety Switch / Proportioning Valve (I don’t know have to copy link from older threads) and can’t help wondering if that has something to do with restricting the pressure release. Has anyone experienced issues in the past? They seem somewhat difficult to find replacements. Are they easily rebuilt?

 

[Ripinator]

Update: over the weekend I replaced the flex line, axle tee, and rear brake lines...and no improvement.
Next step is replacing the Master. Looking at all options, I came across a thread about the Hydraulic Safety Switch / Proportioning Valve (I don’t know have to copy link from older threads) and can’t help wondering if that has something to do with restricting the pressure release. Has anyone experienced issues in the past? They seem somewhat difficult to find replacements. Are they easily rebuilt?

 

[MrMoparCHP]

I had the same issue, replaced the bearings, problem continued, replaced the axle housing, problem solved.
The housing was worn where the bearings make contact.


Alan

 

[stain]

So the axle was moving while under the weight of the car causing the shoes to contact the drums?