drum brake question

ss3011 · 06-06-2014, 08:09 AM

When I did this to my Firebird stocker it was an easy bolt in, with no modifications required. Are the pistons retracted fully on the wheel cylinder ?

Ron Gusack · 06-06-2014, 09:36 AM

I'll check the piston depth first and start measuring stuff. I was pretty sure this would be a bolt on deal. In fact, I think I accidentally put both secondaries on one side when I did my first brake job back in the 60's. It helps to know that this should be a bolt on.

Jim, I'm trying to get all the holding power I can in my foot brake car to allow for higher launch rpm. I know many racers do this and haven't read of any braking problems.

Jim B · 06-06-2014, 10:26 AM

Experience always trumps opinions and theory....listen to the guys who have done it.....

ss3011 · 06-06-2014, 11:26 AM

I also went through the parts books and was able to pick a wheel cylinder with a larger piston diameter. This will increase the force on the shoes.

Run to Rund · 06-06-2014, 11:29 AM

I had John Andreotti at Ott's Friction Supply build me shoes with premium Abex linings. They hold well, and all shoes look pretty much the same, iirc. They aren't prone to fading and yet grip well cold or hot.

Eman · 06-06-2014, 04:30 PM

Shouldn't be a problem. Check to be sure the wheel cylinder pins are engaged properly into the shoe. Make sure the shoes are riding on the pads on the backing plate and not caught on them, if grooved file smooth or replace backing plate. The actual metal shoe is usually the same primary to secondary, they just put the longer lining on the rear one. Remove the shoes and place in the drum to be sure you have the correct shoes and they aren't bent/warped. that's how you check to see if they need arcing back in the day when you arced shoes after you machined the drum.
A crossover to a larger wheel cyl is another trick for more holding power.

fordteacherguy · 06-06-2014, 08:21 PM

I also chamfer the leading edge of the secondary shoe (in the primary position) with a hand file (don't breathe the stuff) so there is a clean release of the new longer shoe. A few strokes will do it....put a shallow bevel transitioning the edge to the shoe.

06-06-2014, 08:09 AM	#1
ss3011 Senior Member Join Date: Feb 2002 Location: Southeast Michigan Posts: 909 Likes: 70 Liked 239 Times in 114 Posts	Re: drum brake question When I did this to my Firebird stocker it was an easy bolt in, with no modifications required. Are the pistons retracted fully on the wheel cylinder ?

06-06-2014, 09:36 AM	#2
Ron Gusack Member Join Date: Feb 2009 Posts: 244 Likes: 1 Liked 7 Times in 6 Posts	Re: drum brake question I'll check the piston depth first and start measuring stuff. I was pretty sure this would be a bolt on deal. In fact, I think I accidentally put both secondaries on one side when I did my first brake job back in the 60's. It helps to know that this should be a bolt on. Jim, I'm trying to get all the holding power I can in my foot brake car to allow for higher launch rpm. I know many racers do this and haven't read of any braking problems.

06-06-2014, 10:26 AM	#3
Jim B Member Join Date: Dec 2008 Posts: 100 Likes: 0 Liked 1 Time in 1 Post	Re: drum brake question Experience always trumps opinions and theory....listen to the guys who have done it.....

06-06-2014, 11:26 AM	#4
ss3011 Senior Member Join Date: Feb 2002 Location: Southeast Michigan Posts: 909 Likes: 70 Liked 239 Times in 114 Posts	Re: drum brake question I also went through the parts books and was able to pick a wheel cylinder with a larger piston diameter. This will increase the force on the shoes.

06-06-2014, 11:29 AM	#5
Run to Rund Senior Member Join Date: Sep 2007 Location: Henderson, NV Posts: 583 Likes: 8 Liked 54 Times in 27 Posts	Re: drum brake question I had John Andreotti at Ott's Friction Supply build me shoes with premium Abex linings. They hold well, and all shoes look pretty much the same, iirc. They aren't prone to fading and yet grip well cold or hot.

06-06-2014, 04:30 PM	#6
Eman Member Join Date: May 2014 Location: E TN Posts: 473 Likes: 16 Liked 133 Times in 76 Posts	Re: drum brake question Shouldn't be a problem. Check to be sure the wheel cylinder pins are engaged properly into the shoe. Make sure the shoes are riding on the pads on the backing plate and not caught on them, if grooved file smooth or replace backing plate. The actual metal shoe is usually the same primary to secondary, they just put the longer lining on the rear one. Remove the shoes and place in the drum to be sure you have the correct shoes and they aren't bent/warped. that's how you check to see if they need arcing back in the day when you arced shoes after you machined the drum. A crossover to a larger wheel cyl is another trick for more holding power.

06-06-2014, 08:21 PM	#7
fordteacherguy Member Join Date: Jun 2007 Location: Federal Way, WA Posts: 238 Likes: 37 Liked 160 Times in 51 Posts	Re: drum brake question I also chamfer the leading edge of the secondary shoe (in the primary position) with a hand file (don't breathe the stuff) so there is a clean release of the new longer shoe. A few strokes will do it....put a shallow bevel transitioning the edge to the shoe. __________________ Brian Thompson NHRA Stock / Super Stock Class P/SA 6665 SS/MA 6665