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1957 Series 75 Front Drum Brakes

Started by Kurt Kjelgaard, November 11, 2020, 12:02:04 PM

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Kurt Kjelgaard

Good to be back after a long hibernation. My 57 Limo has been sitting, waiting maturing, and now I am back to finish the front end.
OK, here is my problem - please be patient, as this is difficult for me to explain.
Attached pictures will hopefully clarify.

On the anchor pin - Grp. 4.3786 in the 46-57 Parts catalog - is fitted a plate underneath the two springs holding the brake shoes up against the anchor pin. This plate is not listed in the text part. The plate fits over the anchor pin and is just over two inches long. The plate fitted on my car has a different shape than is shown both in the parts manuals and in the Service Manual.
A Limo thing?
The plate is not completely flat, but offset a little at one end as can be seen in the picture.

My question is now - is the offset part pointing towards the front of the car or towards the back? See pictures

Is it apparent that the purpose is to hold one brake shoe against the back plate, but which one?

I have a theory that the offset end should be against the brake shoe whose spring is mounted on top of the other spring to compensate for the slight outward pull the is creating, the springs not being in the same plane.

Thanks,
Kurt
Kurt Kjelgaard
1957 7533X Imperial Sedan
CLC #23671

fishnjim

Assuming it OEM and not changed:
I'll have to look in the shop manual.   It's down the garage, I'm in already, just left there, and it's late.  Just thinking about it, it probably doesn't matter, but need to check.  Probably more important if the tab goes down or up.   Try it both ways and see if one binds, if you're in a hurry.   The spring positions will probably tell and curve would follow the top/brake shoe profile   
You probably ought to pick up a shop manual.   

Kurt Kjelgaard

I do have the Shop Manual and three versions of Spare Part Manuals. None of them made me any wiser.
Since the plate in noted as N. L. (not listed) in the Parts Manuals, I have no way to verify if there are different part numbers for the series 75 (and CC). There are differences in other parts of the brakes between the longer cars and the 60 etc. series cars.
Of course, the plate could be non original, but still, there must be an explanation for the offset design.
Kurt Kjelgaard
1957 7533X Imperial Sedan
CLC #23671

Roger Zimmermann

The shop manual is no help for that and I never saw such plates. This plate should be also installed at the rear brakes. How does it look like?
1956 Sedan de Ville (sold)
1956 Eldorado Biarritz
1957 Eldorado Brougham (sold)
1972 Coupe de Ville
2011 DTS
CLCMRC benefactor #101

Kurt Kjelgaard

Hi Roger,

I will take the rear brakes apart today and come back here.
I think the anchor pin is different from the front on Limos and CC, so the plate might also differ.

Will be back soon
Kurt Kjelgaard
1957 7533X Imperial Sedan
CLC #23671

Roger Zimmermann

'57 & '58 cars have the same anchor pin at the front, all series. The rear is different, but that plate could be the same.
1956 Sedan de Ville (sold)
1956 Eldorado Biarritz
1957 Eldorado Brougham (sold)
1972 Coupe de Ville
2011 DTS
CLCMRC benefactor #101

Kurt Kjelgaard

Yep, different anchor pins front and back.

Attached are two pictures of the rear brakes, left and right.
The plates are identical to the ones in front.

And no obvious logic in how the offset end is placed.

When looking at pictures in the service manual and parts manual, the plates are more like
a wide center piece with two "wings". One wing has a marking looking like an indent or maybe a hole.
This could indicate that they are handed in a way, but I can find nothing in the manuals or Serviceman letters.
Kurt Kjelgaard
1957 7533X Imperial Sedan
CLC #23671

Kurt Kjelgaard

Can anybody, perhaps Series 75 or CC folks, help?
Kurt Kjelgaard
1957 7533X Imperial Sedan
CLC #23671

goob

I recently replaced the brakes on our 41. The picture shows the secondary shoe having a 'reinforcement' at the attaching point...the 'plates' look like what you have. The bend in that plate compensates for that 'reinforcement'. Perhaps your shoes are not correct for the car or the plate isn't proper?

Bob Hoffmann CLC#96

I agree. It's been a long time since I did a brake job, but that's what I remember.
Bob
1968 Eldorado slick top ,white/red interior
2015 Holden Ute HSV Maloo red/black interior.
             
Too much fun is more than you can have.

fishnjim

Parts list shows a "CC" commercial chassis drum kit for '57, so the 75 must be on a "CC".   I thought that was for Limos and ambulances but haven't checked.   Found no exploded views, just "regular".   
Since KK's pictures shows it bend back, I think you have to go with it.   Like I said try it and see, if any interference.   Exercise the brake slightly with drum off.
I searched for CC parts/pictures but came up blank.   I did not look in my other period parts catalogs yet, so I'm still searching.   We got "monsooned" here last 2 days, so I didn't get to the garage til today.

The standard drum was used '49 to '59 for all models, not CC, and that part is an "outer guide plate" which is normally diamond shaped with rounds top and bottom.   Common on GM brakes-o-day.   

fishnjim

Was able to verify the 75s take a ~20% larger pad brake shoe, so that guide must go with those shoes.   Still searching.

Jay Friedman

Goob has the correct brake shoes and his photos show how the plate should go.  All 4 wheels should have the plate. 
1949 Cadillac 6107 Club Coupe
1932 Ford V8 Phaeton (restored, not a rod).  Sold
Decatur, Georgia
CLC # 3210, since 1984
"If it won't work, get a bigger hammer."

Kurt Kjelgaard

Thanks to all for weighing in.

Goob, excellent - it makes sense now. Is your car a Limo or CC?

What I can deduct from this is that I have the original "hold down" plates with "wrong" aftermarket brake shoes.

And that my brake shoes are not for the 75/CC brakes, but for 60, 62 and 60S series.

Acc. to the Service Manual, the primary brake shoe lining (forward facing) on is 10.12" long on the shorter cars
and 12.98" long on the longer cars.
All secondary shoes are 12.98" long on all versions.
Braking area for short cars is 222.8  sq. in and for the longer cars 233.7 sq. in.
The difference, of course, comes from the longer lining on the primary shoes.

Can anyone point me to where I can find the correct brake shoes for my car?

Thanks,
Kurt
Kurt Kjelgaard
1957 7533X Imperial Sedan
CLC #23671

J. Russo

I recently did a break job on my series 63. One thing I realized is the spring hooks don't fit correctly if you have that plate installed the wrong way. Both spring hooks should fit on that pin side by side. I had my plate mounted wrong and the springs were too crowded to fit on the pin. Another thing I noticed was when installed wrong, there was a gap between one end of the plate and one of the brake shoe ends that rest against the pin. I believe the plate should be setting against the end of both shoes.
Thanks,
John Russo
CLC Member #32828

Kurt Kjelgaard


I believe that Goobs picture shows exactly what is going on.
One shoe has a reinforcement at the upper end making it thicker.
This in turn makes the plate contact one shoe (the non-reinforced one) with the offset end while the other end lies flat on the reinforced part.
I have two non-reinforced type shoes in each brake, which makes the plate float at one end, not touching anything

John, what year is your car?
Kurt Kjelgaard
1957 7533X Imperial Sedan
CLC #23671

fishnjim

Final:
Did not find any pictures.   The production was around 1000 so they just don't take the time and money to publish those.   I'd think most survivors are in museums, etc.   Not many tooling around.   Head of state, uber riche, etc. used these back in the day, so likely dispersed as well.   Other than TV, I've never seen up close.
I'm fairly certain, but not positive, since not all the info was given, these are commercial chassis shoes/parts.   
About the only way to obtain, less finding a set, would be to have the correct ones "relined".(reuses the steel part)  If you have std pads, then not possible.   Probably why it's like this, PO couldn't get them either.   
You can try the "usual suspects', all cads, CPR, etc. and inquire but don't expect much - rare parts - other than leads.  Then go to museums for help.  US west coast is probably you're best chance for a source.   I haven't come across this, so I don't know if there's someone who specializes in vintage brake pads/limos.
If you keep the std pads, then the std outer guide plate is fairly common and used in a decade worth of vehicles. 
Beyond that you're into an upgrade to disc, etc. or accept the fact it won't stop as well, if legally allowed in your jurisdiction.
ps: Always helps in these inquiries to put down all the facts first, model, what's been done/not done, so not to speculate and waste time.   But I enjoy the hunt.
I'll check the interchange if another brand/year used same.

goob

Kurt -

  I purchased the relined brake shoes from my local napa store. Our car is a 1941 series 62 convertible coupe, so it's not a commercial chassis.

Gary Grieshaber

savemy67

Hello all,

This thread is a great example of the wisdom of crowds.  Keep up the good work!

Christopher Winter
Christopher Winter
1967 Sedan DeVille hardtop

fishnjim

Here's what the interchange says:
Cadillac only.   
75 is just a different lining, as I mentioned, but doesn't resolve the guide issue.   So default has to be commercial chassis.
Look up index for '57 75, then go to "4" interchange and see what other years fit. 
'55-'59 75 and 52-55 & 59 CC.
The second one is clearer.   First was fuzzy on the interchange.