55.2-59 1959 got bigger brakes... since when?

[daveshilling]

I found this ad claiming that 1959 Task Force had larger brakes for 31 and 32 series light duty...what are they talking about?

[1project2many]

What?? Is that a dealership ad or a GM ad?

All I can find is that the GM Heritage Center vehicle information sheet shows 11X2 rear brakes for the '59-'60 and 11X1-3/4 for rear on '55-'57.

Ads and documentation for the '59 cars show larger brakes. Possibly a dealership employee was confused when creating ad copy?

[daveshilling]

Originally Posted by 1project2many

What?? Is that a dealership ad or a GM ad?

All I can find is that the GM Heritage Center vehicle information sheet shows 11X2 rear brakes for the '59-'60 and 11X1-3/4 for rear on '55-'57.

Ads and documentation for the '59 cars show larger brakes. Possibly a dealership employee was confused when creating ad copy?

It sure looks like a GM ad.. https://www.flickr.com/photos/autohistorian/29200879722

[1project2many]

That's a cool ad! Definitely looks like a GM product.

I decided to blow an evening digging through old GM parts books on gmpartswiki. This is partly because the rear shoes on my '57 appear original and are finally in need of replacement and I'm hoping I can scrounge up a forgotten set of shoes somewhere.

It looks like gm switched from 11 X 1-3/4 rear shoes to 11 X 2 rear shoes on trucks in '59.

Rear shoe part number 3695709 for '51-'56 changes to 3742645 also used for '57 models then to 3752313 then to 5470547.

Front shoe part number 3696177 '51-'56 changes to 3732507 also used for '57 models then to 3752312 same as F + R of '59 -'62 trucks.

GM says F + R drums are the same from '51 - '62 so maybe the larger shoes could be installed in the rear? I would guess the 59 + rear wheel cylinders would be machined to space the C/L of the cylinder 1/8 inch farther from the backing plate but that may not be the case. Maybe they use the same cylinders as the 55 - 57 front?

Checking through GM parts books it appears that 53-62 Corvette "Heavy duty" brake shoes also fit our trucks. Vette metallic shoes are part no 3794194 R and 3794191 F. Werner Corvette lists an OE set of F + R for $675.00. Still need the special heat treated return springs but it's just the thing for a guy looking to build a vintage hotrod truck with period correct parts.

[Daze57]

very cool information !!!

[dsraven]

if the shoes got wider then probably the wheel cylinders or the backing plates are different too. maybe something to check.
if you were to prioritize a brake upgrade the first thing on your list should possibly be a dual system master cylinder. even a concours judge would probably not fault you for that one because it is a safety item.

below is a link to a page with possibly a good read for those contemplating a brake upgrade (and other great brake info). bigger isn't always better unless the whole picture is looked at. its all about bias from front to rear. since a lot of us have modified our rides the stock bias pattern could be out the window so an adjustable proportioning valve could be in our future. that is a great reason to use the tech line from the supplier/manufacturer of our choice. rear wheel skid ain't your friend. trucks are light in the rear to start with so, unless you upgrade for load capacity, be aware that a larger brake surface out back also impacts what's going on up front. and vice versa. this is why some of the newer trucks have that load valve at the rear. more load meant more brake pressure to the rear. less load, well you get the idea. it was a valve connected to a link from the rear axle. axle moves away from frame-less brakes and wheel lock up. axle closer-more brakes

https://www.brakes-shop.com/brakeped...brake-upgrades

[1project2many]

Good points for anyone upgrading brakes. I suspect there was some standardization going on and the trucks were simply issued larger brakes. Cars received wider brakes because it reduced brake fade. It doesn't really improve stopping power. The truck weight bias is so heavily forward of centerline that rear brake improvements should be much lower on the list imo.

[_Ogre]

Originally Posted by 1project2many

I decided to blow an evening digging through old GM parts books on gmpartswiki.

true sign of a truck nerd, i bow to 1p2m

[daveshilling]

Originally Posted by 1project2many

That's a cool ad! Definitely looks like a GM product.

I decided to blow an evening digging through old GM parts books on gmpartswiki.

Glad you did, really interesting! I also noticed that some parts suppliers were listing brake shoes for 55-58, so that confirms it. I've never had to do drums on a 59 until now, so this is timely info indeed.

I also suspect that it was just easier to use one brake shoe part # instead of two, and the marketing boys just spun it as an enhancement.

[daveshilling]

To further complicate the issue, I have what *MIGHT* be a positraction rear end in my new '59 that I will need to do brakes on soon.

It's a Spicer 45 rear, which were standard with GMC light duty but not on Chevy's, and the only reason I can see that a Spicer 45 would end up under a Chevy is if the posi was ordered, or the guy asked for a heavy duty rear axle and they sourced a GMC part for him instead.

This parts Wiki lists the rear brake shoes as a differentiated part for 58-59: http://www.gmpartswiki.com/getpage?pageid=226187

Which is also interesting, because the posi rear was only advertised as a '59 improvement, although maybe late-year 58's were able to special order.

[1project2many]

Some interesting questions...

I'm nowhere near as clear on the GMC parts books but it looks like the D45 shoes part no 2405962 also fit D44 axles all the way back to '35.
http://www.gmpartswiki.com/getpage?pageid=23953
Same part number shows for 58-59 w/ posi trac in the Chevrolet parts book:
http://www.gmpartswiki.com/getpage?pageid=66815

I've never seen a posi rear in a Chevy truck so this helps confirm for me that Chevy used a Dana 45 if customer ordered a posi.

Looks like a cool find!

[mr48chev]

I've done hundreds of brake jobs most when I was the front end/ brake mechanic in a firestone store but wouldn't have known that 59 was different than 55/58. For me it was always take the shoes out of the box, match them to the old shoes, finish the brake job.

I don't remember any trouble with GM brakes not being the right ones except when the service writer got the info wrong and ordered parts for the wrong year. Fords after the mid 50's early 60's were an absolute pain though. You have to have the year correct, model correct, engine and transmission correct to get the right brake shoes and drums for some models.

I'd think that a good number of car/truck salesmen in 1959 didn't know that you could even get a limited slip/posi in a 59 truck.

[1project2many]

Long story short, it looks like the secret is the backing plates. If a guy wanted to run 2" rear brakes he would locate a set of backing plates from a '59 through '75 GM (not Dana) 1/2 ton rear axle.

1" diameter wheel cylinders 5465039 (L) and 5465038 (R) fit '55 - '72 1/2 ton non-posi trucks.
http://www.gmpartswiki.com/getpage?pageid=22337

Backing plates # 3984867 (L) and 3984868 (R) fit 1/2 ton non-posi axles from '59 up to '75.
http://www.gmpartswiki.com/getpage?pageid=22391
http://www.gmpartswiki.com/getpage?pageid=61101

These plates go through a series of number changes along the way to the numbers above:
L 3775369 --> 3840929 --> 3896883 --> 3984867
R 3775370 --> 3840930 --> 3896884 --> 3984868

For daveshilling and anyone else who happens to get a '58-'59 Chevy with Dana / Posi axle, backing plate #'s are: L 2346817 R 2346816

I also stumbled on an interesting part number for the guys with 2" rear brakes. Self adjusters were installed by GM beginning in '63 on cars and '64 on trucks. A "Self adjuster kit" 3826517 was available from GM to convert '59-'62 cars and '59-'63 trucks to the later configuration.
http://www.gmpartswiki.com/getpage?pageid=66808

A GM service bulletin for this kit describes "new" self-adjuster operation, has part numbers, and describes the installation procedure. Reading through the procedure it seems as though a person with 1 3/4" brakes, following the same steps and using the equivalent parts from a set of 2" brakes, could install self-adjusters on the rear of an older truck. And since the front brakes already have 2" shoes, it stands to reason they could also be upgraded. The bulletin can be seen here: https://www.corvair.org/chapters/cor.../S-AB/S-AB.pdf

And for anyone who just needs a set of shoes, Napa is showing 11 X 1-3/4 rear shoes up to '57 and 11 X 2 after that. TS9 is listed for the 55-57 rear and UP228 (there are fleet shoes available also)for the '58+ rear and '55-'59 front shoes. With all the overlap, if I owned a '58 or a truck that may have received an axle swap I'd probably measure shoe width before ordering new shoes.

[1project2many]

Fords after the mid 50's early 60's were an absolute pain though. You have to have the year correct, model correct, engine and transmission correct to get the right brake shoes and drums for some models.

Yes, and Ford can still be a nightmare. I was looking for a computer for a 2009 model Explorer. There were 14 different computers listed with no information about the differences. Ultimately it came down to two different computers and seven software updates for each. Ugh.

I've also had trouble with International trucks. You can't just show up at the parts counter with year/make/model. You almost have to know the family of the guy building the truck in order to get the correct parts.

[mr48chev]

I get you there, I have a 92 4.0 ranger that I bought to fix and sell or use as a daily beater. Engine will run but has a dead miss. Thought I would hook my scanner to it and no dice, no scanner connection on the early 92 Ranger. No distributor , crank triggered and it fires two cylinder at a time. Enough ranting about my OT mess though.

At least Chevrolet didn't decide mid year 58 that they needed to upgrade the rear brakes. I've run into few mid year Chevy changes and they don't put less braking power on a six cylinder car than a V8 car. You could order the "police/taxi" brake package on some full size cars if you knew to though.

[_Ogre]

Originally Posted by 1project2many

1" diameter wheel cylinders 5465039 (L) and 5465038 (R) fit '55 - '72 1/2 ton non-posi trucks.
Backing plates # 3984867 (L) and 3984868 (R) fit 1/2 ton non-posi axles from '59 up to '75.

good old gm, using the same part for years, a pattern that continues today
every time i work on a ford, i forget that they change part # mid year, possibly multiple times

[1project2many]

Something interesting, maybe, for a few. I removed a factory Hydrovac from a '57 GMC to use on a Chevy when I was a kid. One thing that surprised me was the copper brake lines. I knew it was illegal and that steel should always be used.

Looking through a GMC parts book today I see that folks looking for brake a line for a Hydrovac equipped truck were directed to make the lines from a 25' roll of copper tubing. So I guess that answers that question.
http://www.gmpartswiki.com/getpage?pageid=24167