robsgp : brakes (still)

brakes (still)
Post by robsgp on Sept 6, 2006, 9:22pm

Sorry I keep asking questions about this but I'm still in the process of overhauling my brakes.

I saw the post by someone who had their brake shoes relined by American Industrial Brake in Westminster CO so I gave them a call. I was quoted $62 & change per axel. I mentioned the long and short lining and they said they would put the longer lining on all shoes. Is there any problem with that?
They also asked me to mark on the shoe what position it would be installed. Since they were all wrong when I took them off how would I know?
And they suggested I measure the drum diameter to see if they could install a thicker lining. Mine appear to be pretty close to 13".
Thanks, Rob

Re: brakes (still)
Post by jed on Sept 6, 2006, 9:34pm

I just had mine relined by Page brake in Salt Lake...about $50 per axle... they did them just like stock with a long lining and a short lining. Thickness was 1/4 inch but I'm not sure if thicker would work.. It might cause my drums are worn a little. How thick do they want to put on?

Re: brakes (still)
Post by kwai on Sept 6, 2006, 9:43pm

No problem with the long lining on all the shoes. Easier to install because you don't have to pay attention to which shoe is which.

Re: brakes (still)
Post by jed on Sept 6, 2006, 9:49pm

Good point!!!

Re: brakes (still)
Post by luckypabst on Sept 6, 2006, 9:54pm

You need the short and long linings, it's a big part of the whole "self-energizing brakes" idea. It's also why the brakes don't work in reverse as well as in forward.

Chris

Re: brakes (still)
Post by wrecker on Sept 7, 2006, 8:38am

Chris, could you explain the self energizing brakes. I just changed the rear ones in my 97 silverado and was surprised to see the shoes were all exactly the same. No length difference at all. What is the length difference for exactly?

Re: brakes (still)
Post by brute4c on Sept 7, 2006, 9:02am

According to the manual, the max drum diameter section reads:


Quote: <TABLE class=bordercolor cellSpacing=1 width="90%"><TBODY><TR><TD width="100%"><TABLE class=quote cellSpacing=0 cellPadding=2 width="100%"><TBODY><TR><TD width="100%">Using brake drum micrometer, check all drums. Should a brake drum be rough and scored, it may be reconditioned by grinding or turning in a lathe. Do not remove more than .030? thickness of metal, .060? overall diameter. If a drum is reconditioned in this manner, either the correct factory-supplied, oversize lining .030? must be installed, or a shim equal in thickness to the metal removed must be placed between the lining and shoe so that the arc of the lining will be the same as that of the drum.</TD></TR></TBODY></TABLE></TD></TR></TBODY></TABLE>

So that looks like instead of a thicker shoe, the proper method to give the shoe a larger diameter is by shimming behind it...I know this method is sometimes used on big trucks...which we are more akin to...

Re: brakes (still)
Post by redneck1 on Sept 7, 2006, 11:50am

Rob,I had my shoes relined with a webbing design,$60 per axle.
as long as the brakes are adjusted they work better than stock,(ie) no brakes at the F.E.
I am pleased with them.
Redneck1

Re: brakes (still)
Post by fsjguy on Sept 7, 2006, 3:49pm

That was me who had them done by the place in CO. He didn't mention long/short linings when I went in. (I brought them in, in person) They were marked FRONT (as in front axle) when I got them back, however. The front sets had thicker linings that wouldn't fit (even with the adjuster as short as it could go), so I put one thick on up front, and one thick on in the rear. IIRC, the linings were not different lengths.

Since you're in MO, I'd think there would be a brake shop a little closer that you could go have a face to face with.

Re: brakes (still)
Post by robsgp on Sept 7, 2006, 6:58pm

You'd think in a town the size of St Louis I could find a place to get this done, but I have struck out both on the web and in the phone book. Every place I've called says "Nobody does that anymore". I called All-Frictions in CT and they said $20something per shoe.

I'd like to know more about the self-energizing brake idea too...

Look's like from Jon's research I could use a lining up to .030 thicker but since I seem to have misplaced my brake drum micrometer, I better stick with standard.

Will,
Where did you have that done? You sort of needed your brakes to work better in reverse, if I recall... ;-)

Thanks guys.

Re: brakes (still)
Post by luckypabst on Sept 7, 2006, 10:24pm

The basic principle of the self energizing brakes is that when the shoes expand to touch the drum, friction against the drum causes the shoes to rotate a bit with the drum rotation and "wedge" themselves, or create more pressure than what just the wheel cylinder can provide. The short lining aids in the leading shoe's "digging in" action.

This is the reason the shoes are not rigidly attached at the adjuster or the retainers - it allows them to float inside the drum.

Here's something I found quickly but you'll get a lot of responses related to bicycles if you google it:
http://www.raybestos.com/OnLineTraining/cpt-007.htm

From that link:
On a self-energizing brake, the secondary shoe does approximately 70% of the braking. It has a longer lining than the primary shoe.

Chris

Re: brakes (still)
Post by brute4c on Sept 8, 2006, 9:29am

Great info Chris...thanks for the post and the link!