Breaking distance

[dinof]

I read about grinding brake shoes frequently in this forum, but my own Ohio experience is that no shops offer that particular service anymore. I wonder if this is more of a recollection than an actual commercial service offered today.

One interesting home solution that I've not tried yet, is to measure a suitable strip of sandpaper and use contact cement to glue it to the inside circumference of the drum. Install the drum and turn until the brake shoes conform properly.

If I try it, I'll start with 120 grit and go from there.

Just be careful not to breath any asbestos in. We used to sell asbestos sheets in the hardware store, so I'm going to avoid doing this one

[JIMN]

When they are adjusted right they can put you through the windshield....

[artificer]

We are really way off what the OP asked but in the interest of better information....I have always said:
Take the drum/hubs to a proper brake specialist not those franchise joints like Quicky Brakes etc.

Have the specialist skim as little as possible to remove wear, grooves etc. from all the drums.
The drums should ALL now be the same ID [internal diameter] & within manufacturer's limits.

1. Prefered....Next have the same brake specialist bond linings to the shoes to suit the amount of material removed. I would always use bonded BUT
2. If you have to use riveted original dimensioned linings these new linings are [brass] shimmed away from the shoe exactly the radius [not diameter] thickness of the drum removed.
This was accepted practice when oversize linings stopped being made or weren't available.
Basically when demand & this fixed anchor system died a natural death.

Realise that most new brake people have no comprehension of the Jeep's fixed twin anchor drum brake system, the need for concentricity to be adjusted & how this is achieved initially, if they know anything about drum brakes @ all.

Later servo type drum brake systems with floating shoes, some specialists may know about & they assume your's are the same. THEY ARE NOT.
The later type are made concentric with one simple adjustment to the shoe circle diameter, or a self adjusting mechanism.
So they don't have the same adjustment problem/s as twin fixed anchor systems.

[dinof]

To be honest here John, the op's question really can't be answered correctly to compare to what the system would be doing on a normal brake sequence. It's not a BAD QUESTION, but everyone that goes out to test their jeep will all have different readings because of the pressure they push down on will vary. And then the op might deem his brakes not correct and might tear into things when they are really ok. As you know, barring locking up the brakes, one and all could report big differences in footage they obtain.

I think rather than guess, the op should get a TM and inspect the system for wear patterns, leaks, pulling to one side and check the system that way.

Dino

[dpcd67]

If you do not have a short BRAKING distance, you will quickly find out your BREAKING distance.

[gearhead]

Braking distance is and always be VERY subjective.
Even today (electronic nannys on or off) reaction time is the greatest factor in braking distance.
Best to allow proper spacing for the speeds involved, of course keep the braking system in top shape!!

Ed S

[tamnalan]

I read about grinding brake shoes frequently in this forum, but my own Ohio experience is that no shops offer that particular service anymore. I wonder if this is more of a recollection than an actual commercial service offered today.

One interesting home solution that I've not tried yet, is to measure a suitable strip of sandpaper and use contact cement to glue it to the inside circumference of the drum. Install the drum and turn until the brake shoes conform properly.

If I try it, I'll start with 120 grit and go from there.

Just be careful not to breath any asbestos in. We used to sell asbestos sheets in the hardware store, so I'm going to avoid doing this one

I suspect the asbestos concern would be mostly for people who are using NOS brake linings. I doubt the new shoes offered today use asbestos. Good advice though, regardless of the lining composition. I would do it outside at slow drum RPM and use a vacuum.

[Chuck Lutz]

Read artificer's post!
Brake shops are mandated by state law regarding how much they can "turn" the drums to clean them up. Once they are out of spec, they will refuse to do that. Take your drums and shoes to a shop and have the drums "turned" and the shoes "arced" to match the drums....otherwise new shoes will not get 100% of their surface against the drum and the effeciency of that drum/shoe is reduced accordingly.

NEVER just put four drums on the jeep "because I got two Rs and two Ls on the lug threads!". Have all four done at the same time and you will get the best results possible.

PS, if one matched pair have been turned a bit more than the other matched two, then the ones with the most meat go on the FRONT!.

FYI...1/4 ton trailers will be found with drums that have never been turned and you can swap out a pair of others off the jeep that have been turned to the max and refused by the shop to be turned any further. Those "good" ones are the ones to take to the shop and to put on the front axel.

[mpg]

Thanks everyone!!

[dinof]

Skip the vacuum. Your shop vac probably isn't able to filter asbestos. Safer without it. And brush it clean, never use the air compressor. And wash down the floor with water only. You can also use a wetted paper towel to clean the brake linings & shoes.

Dino

[tamnalan]

Is anyone actually finding a shop today willing to "arc" a set of brake shoes?

Business contact info if so?

PS: I'm thinking the vacuum is more to clean up the debris than for health concern.

[gearhead]

A few here in Pa, the few that even turn drums anymore!

Ed S

[artificer]

This process is correctly known as either radius or arc grinding.

There are plenty, especially shops that do drum brakes &/or truck brakes as some bendix air brake systems still use fixed anchors & the shoes on them have to be radius ground.
Do some simple searching on something like .....US/local companies who arc brake shoes?
One can also find information on old vehicle forums regarding folk & methods they have used including Alan's proposed sandpaper method used on Mopar's. Mopar vehicles back then used the same bottom anchor system as the Jeep:

At my local hardware store I found a roll of sticky back sand paper.
For each drum, I cut a strip of sand paper long enough to go around the full inside of the drum and stuck it in.
Next I used a sharpie to mark some cross hatches on the shoes and then put them in the drum and rubbed them back and forth until the cross hatches were gone. That only took a minute or two a piece.
I did each wheel separately so the shoes were lapped/arced to the drum they were being used with.

At this point I knew that the shoes were arced to the radius of the drum minus the thickness of the sand paper. The paper I got was a little thicker than I wanted but nonetheless the result was a lot closer than I started out with and it got the shoes close enough to allow me to use my Ammco shoe aligning tool.

Total cost was a couple of bucks for the roll of sand paper and I only used a little bit off the roll.

Since then I've acquired an Ammco shoe grinding tool but I haven't used it yet as the above has been good enough to get me the best brakes I've had in years on that car.