New Brake Linings

Discussions related to braking systems.
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GJBINSC
Posts: 108
Joined: Wed Jul 19, 2017 9:31 am

New Brake Linings

Post by GJBINSC » Mon May 07, 2018 5:57 am

I have an issue with new brake linings on my 901. I sent the brake shoes to Max Merritt for relining. When I tried to install the brake drum it went on with much force. I slacked off all the adjustments, and even disconnected the brake cable so that the cam lever was completely vertical. The drum will not turn easily, and takes two hands to turn it. The brakes seem to be pushed to the to top of center and the primary shoe is touching the drum for its full length. When I tried to move the anchor pins to the lower position, it still did not relieve the tension on the primary shoe. Clearance at the secondary shoe ( bottom ) is far in excess of the recommended .005 as outlined in the Bendix service letter. Could the linings need to be "scraped in" to make them round ? Lining material seems to be of even thickness all the way around but with a feeler gauge I have multiple spots where it touches the drum. On some old cars, you had to" drive" the linings in to get them round, but that will surely overheat the drums and cause warping.

Dave Czirr
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Location: New Jersey

Re: New Brake Linings

Post by Dave Czirr » Mon May 07, 2018 6:56 am

"Driving in" to "seat" the linings is a very poor practice and only needed if the wrong parts are used and/or incorrectly installed. You have the 3-shoe Bendix?

I don't have my specs handy for the 901/02, but what thickness lining did Max use? Depending on year and model both 1/4" and 3/16" were used. Both the 900 and the 905/906 used 3/16"

GJBINSC
Posts: 108
Joined: Wed Jul 19, 2017 9:31 am

Re: New Brake Linings

Post by GJBINSC » Tue May 08, 2018 6:05 am

Just an FYI, I got the number of the shop that did the work for Max Merritt, and called him. It appears that the lining material is a bit thicker than Packard specs. He said it may be due to the fact that it is now a metric measurement. He said that I must sand them down a bit to fit. He thought that Packard did that at the factory as lining material has always been a bit inconsistent anyway. He said that contour sanding was pretty normal. He suggested I use 120 grit and work them down with a block. I tried that, but the high metal content of the linings made the sand paper useless pretty quick. I resorted to a medium mill file and it worked perfectly. Got the offending areas contoured in about 15 minutes. Drove it after final adjustments and was able to lock up the front brakes on the hard stop. Need a bit more adjustment to the rear, but pretty close at this point.

Dave Czirr
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Location: New Jersey

Re: New Brake Linings

Post by Dave Czirr » Tue May 08, 2018 6:19 am

Glad you got it solved, I'm disappointed it Max's choice of shops, standard 3/16" and 1/4" roll linings are common here in local brake shops.

Contour-grinding of shoes (linings) to match the OD of the drum is part of a good, comprehensive brake job, giving 100% shoe/drum contact at installation, and especially important if the drums have ever been turned. Certainly a far-more precision operation that sanding or filing. The problem of course is that the shop that does the lining work also needs to have both the drums; one of the reasons why I prefer a local brake shop.

GJBINSC
Posts: 108
Joined: Wed Jul 19, 2017 9:31 am

Re: New Brake Linings

Post by GJBINSC » Wed May 09, 2018 5:57 am

Yes I would have preferred to have a shop do it too, but unfortunately there are none in my area, and moving the car 100 miles or more to get to one was not possible. The perils of living in a relatively new area, although there are many old cars in the area we all have felt the pain of not having those old school shops nearby.

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