A Body LARGE bolt pattern rear brakes

-
Bill Dedman

Bill Dedman

bill dedman
Legendary Member
Joined
Oct 16, 2007
Messages
3,987
Reaction score
140
Location
Conway, Arkansas
On ebay, there's a company selling A-Body rear axles with the 4.5" (large) bolt pattern. In the axle information it says they also have '73-up LBP brake drums that will allow you to keep your original
8.25" rear A-Body brake hardware (backing plates, shoes, etc.)

Does this mean that if you simply replace the axles with ebay ones with the new larger bolt pattern flanges, you can use any '73-up large bolt pattern brake drums from an A-Body car?

That would be ideal, if it's true. For some reason, I thought you needed the B-Body brakes to go with the LBP axles, but now that I think about it, the brake drums off any '73-up Duster, or Dart with the large bolt pattern and an 8.25" rear should work, right?

Any info will be appreciated.

Bill
 
You will need to get the matching backing plates, small bolt pattern A-body ones are different and will not work properly. Most B,C,E etc ones will fit. I used 11" cop car rear drums on my 66 Valiant.
 
bill,

you can use your LBP 8.25 backing plates...brakes..and drums with those axles..i have swapped out two 8 3/4 like that...

but one thing according to Dr Diff...if you have the clutch style sure grip...watch out for the Yukon axles...he says they are too short to properly engage the sure grip.....in other words..they are too short...they only engage about 1/8 inch..

one thing went your order from him...he asks questions about your 3rd member...kind of kinky...
 
OOOps, you are right, 8 1/4 ones will work, I miss read and thought you had 8 3/4 sbp drums.
 
Bill,if your going to spend good money on some axles buy some good quality ones that are worth your money.. ie: Moser,the rest are NOT of as high quality...
 
stroked 340 said:
Bill,if your going to spend good money on some axles buy some good quality ones that are worth your money.. ie: Moser,the rest are NOT of as high quality...
Click to expand...

So, who would you recommend, as a supplier???? Just Moser?

I don't want something that's going to end up with twisted splines after a few passes.

Thanks for the advice.

Bill
 
My so-called brain isn't functioning very well right now, and try though I might, I still am not 100-percent sure about this: After I put 4.5"-bolt circle axles in my 8.75" A-body housing, is there any reason why I can't use a pair of '73-up drums off a Duster with an 8.25" housing?

I don't want to go to the trouble of putting the whole B-Body hardware system (backing plates, shoes, etc.) on my car if an A-Body drum from a 1973-up 4.5" bolt circle, 8.25" rear end willl work.

I'm pretty sure from what folks wrote that it will.... just want to be certain.

Thanks for any info!!!

Bill, in Conway, Arkansas
 
70aarcuda said:
bill,

you can use your LBP 8.25 backing plates...brakes..and drums with those axles..i have swapped out two 8 3/4 like that...

but one thing according to Dr Diff...if you have the clutch style sure grip...watch out for the Yukon axles...he says they are too short to properly engage the sure grip.....in other words..they are too short...they only engage about 1/8 inch..

one thing went your order from him...he asks questions about your 3rd member...kind of kinky...
Click to expand...

Can you recheck your facts on this one? By saying that "someone" says "there is only 1/8" of engagement" you are passing on, what I believe is false information. I believe he had mentioned that the Yukon axles, have 1/8" less engagement than the axles he cuts/supplys. If I remember correctly, that is what he told me. 1/8" total engagement on yukon 8.75 axles is incorrect. Another 8.75 issue is the thrust button, NOT needed for green bearing applications, but is needed for standard axle bearings. That can also change the effective spline engagement.
 
Bill Dedman said:
My so-called brain isn't functioning very well right now, and try though I might, I still am not 100-percent sure about this: After I put 4.5"-bolt circle axles in my 8.75" A-body housing, is there any reason why I can't use a pair of '73-up drums off a Duster with an 8.25" housing?

I don't want to go to the trouble of putting the whole B-Body hardware system (backing plates, shoes, etc.) on my car if an A-Body drum from a 1973-up 4.5" bolt circle, 8.25" rear end willl work.

I'm pretty sure from what folks wrote that it will.... just want to be certain.

Thanks for any info!!!

Bill, in Conway, Arkansas
Click to expand...

Bill if you are converting an 8 3/4 rear to LBP you MUST replace the rear brake assembly COMPLETELY ... backing plates and all .... , the 73-up setup off the 8 1/4 is the same as the B body brakes you are asking about .
 
Bill Dedman said:
So, who would you recommend, as a supplier???? Just Moser?

I don't want something that's going to end up with twisted splines after a few passes.

Thanks for the advice.

Bill
Click to expand...

Bill,theres a guy on here thats a Moser distributor,i'm not sure if he deals with the exact same axles i have,but you can rest asured any thing Moser makes is going to handle the power your putting out,i had them for 2 seasons now no issues whatso ever,and trust me my stroker was putting out over 520 h.p. as far as twisting goes none!!!
 
JohnRR said:
Bill if you are converting an 8 3/4 rear to LBP you MUST replace the rear brake assembly COMPLETELY ... backing plates and all .... , the 73-up setup off the 8 1/4 is the same as the B body brakes you are asking about .
Click to expand...

Thanks, John. I didn't know that. Exactly what I needed to know, and good information!!! I appreciate it.

Bill
 
stroked 340 said:
Bill,theres a guy on here thats a Moser distributor,i'm not sure if he deals with the exact same axles i have, but you can rest assured, anything Moser makes is going to handle the power you're putting out. I had them for 2 seasons now... no issues whatsoever,and trust me, my stroker was putting out over 520 h.p. As far as twisting goes, none!!!
Click to expand...


I know the Moser axles are good. Maybe I can find out who the Moser guy is on FABO.

Thanks for the heads-up!!! 8)

Bill
 
swing69 said:
Can you recheck your facts on this one? By saying that "someone" says "there is only 1/8" of engagement" you are passing on, what I believe is false information. I believe he had mentioned that the Yukon axles, have 1/8" less engagement than the axles he cuts/supplys. If I remember correctly, that is what he told me. 1/8" total engagement on yukon 8.75 axles is incorrect. Another 8.75 issue is the thrust button, NOT needed for green bearing applications, but is needed for standard axle bearings. That can also change the effective spline engagement.
Click to expand...

http://board.moparts.org/ubbthreads...ds=+DoctorDiff&topic=&Search=true#Post4899697


about half way down the page...doctor diff post..."I sold at least as many Yukon A-body axles as ANY other Yukon dealer. Ever since I bought the first batch about 8 years ago, I have been trying to get the manufacturer to make the axles the correct length for use with ALL sure-grips.

I quit selling those axles a couple years ago because I got tired of asking everyone what type of sure-grip they are running. Most people don't even know without checking. I also did not like having to warranty stripped axles because the inner side gear only had 1/8" of spline engagement.

Judging by their latest website ad, Mancini Racing must have finally realized the problem with the axles, because the customer must now specify their diffential type when ordering.

The best part is, I now offer completely assembled, CUSTOM LENGTH, 30 AND 35 spline axle packages machined specifically for the application (by me) for about the same price as partially assembled off the shelf stuff"

now reading it again...he says the inner side gear....

i may have misread...
 
I just ordered Moser axels 28 inches and all you have to do is let him know what size brakes.I,m useing my old 8 1/4 backing plates and brakes(10x2 1/2) with green bearings and 1/2 x 2 inch studs.I have the green bearings in my other car that is 452hp and a 4 speed and have no problems with them.Good Luck with whom ever you decide to purchase from.:cheers:
 
Bill, 72 down A-bodies came with 1 3/4" wide brake shoes, the later A-bodies, B bodies and C bodies came with 2.5" wide brake shoes. The axles you are looking at have an offset to work with the 2.5" wide brakes whether they are 9", 10" or 11" in diameter. Whatever drum you select you will need backing plates and the rest of the hardware to go with that size drum. The 73+ 10" a-body drums are a nice match to the 11" 73+ front disks and the drums and shores are readily available.
 
Thanks, Dave. That clears up any and all mis-conceptions I have had about this whole swap deal (and, I had a few...)

I called Moser today and found out what I needed to know from them.

My tab would end up somewhere around $550.00+ for Moser axles, wider brake drums, and the backing plates and miscellaneous hardware I'd need to swap to a LBP setup.

I believe that for now, I'm going to replace the 7/16" OEM wheel studs with some half-inch, grade 8 studs in these 4" bolt-circle axles, and enlarge the existing holes in my SBP drums to accommodate the half-inch studs.

I only run 8" Drag Radials at the strip, and don't even have a high-stall converter or a low-gearset in this 904.

I don't think I'm going to hurt these axles, at least, until I get a 3,500rpm-stall converter.

I can use that $550.00 to replace the riding lawnmower that got stolen out
of my backyard on Christmas eve.

Thanks a bunch for the clear-as-a-bell explanation of the vagaries of the different brake setups for the various rear-end configurations. You should be writing tech manuals, Dave!

Bill, in Conway, Arkansas
 
Bill Dedman said:
Thanks, Dave. That clears up any and all mis-conceptions I have had about this whole swap deal (and, I had a few...)

I called Moser today and found out what I needed to know from them.

My tab would end up somewhere around $550.00+ for Moser axles, wider brake drums, and the backing plates and miscellaneous hardware I'd need to swap to a LBP setup.

I believe that for now, I'm going to replace the 7/16" OEM wheel studs with some half-inch, grade 8 studs in these 4" bolt-circle axles, and enlarge the existing holes in my SBP drums to accommodate the half-inch studs.

I only run 8" Drag Radials at the strip, and don't even have a high-stall converter or a low-gearset in this 904.

I don't think I'm going to hurt these axles, at least, until I get a 3,500rpm-stall converter.

I can use that $550.00 to replace the riding lawnmower that got stolen out
of my backyard on Christmas eve.

Thanks a bunch for the clear-as-a-bell explanation of the vagaries of the different brake setups for the various rear-end configurations. You should be writing tech manuals, Dave!

Bill, in Conway, Arkansas
Click to expand...

What are you going to do about the WHEELS ??? The 4" BP wheels are setup to use 7/16 wheel stud hardware
 
I have Centerllines on the back that have dedicated lug nuts that fit the 7/16" studs, but have load-bearing shoulders that are of a much larger diameter for the holes in the wheels. I can get lug nuts with that same (larger) outer diameter that work with half-inch studs.

I think that'll work, since I won't be using OEM wheels.

100_3181-2.JPG
 
Bill Dedman said:
I have Centerllines on the back that have dedicated lug nuts that fit the 7/16" studs, but have load-bearing shoulders that are of a much larger diameter for the holes in the wheels. I can get lug nuts with that same (larger) outer diameter that work with half-inch studs.

I think that'll work, since I won't be using OEM wheels.
Click to expand...

Well the first thing you should do is get a 1/2" lug nut and make sure it fits the wheel because if it doesn't everything else is a waste of time and money .

Bill , dumb question , what tires are on those rims ?? if you are using a sticky compound tire you are just wasting money and time as you WILL break the stock axles eventually .
 
John; there are no dumb questions; I appreciate your interest.

Those tires are B.F. Goodrich T/A Drag Radials, 26"-tall and 8" wide. It was the biggest tire I could fit in there without mini-tubbing it, or raising the car excessively. They don't hit anywhere, but they're really close on the inner fender panel.

You're 100-percent keyrect on scoping out the lug nut situation. I'll do that forthwith!

Insofar as axles go, I used to have a '64 Valiant with a mid-12-second 340 motor. It was a 4-speed car. I ran a 2.49:1-geared cast iron (A-333?) stock ratio '71 Duster 4-speed with a 3,000-pound Hayes pressure plate that had the counterweights cut off for a clean release at 6 grand. It worked like a charm, and I could power shift that thing unerringly, and did, for about 3 or 4 years. It was a piece of cake.... not slick-shifted, but nevertheless, was really easy to shift. I had put a coulple of longitudinal braces on the firewall to keep it from moving under the stress of that clutch, which took a pretty healthy amount of foot pressure to release all the way.

I ran some soft-compound (I think they were #140) M & H Stock Eliminator 7" slicks (that's how long ago it was; Stockers had to run 7" tires!) that were 29" tall, and I had a 4.56 Sure Grip (489 case) and some slapper bars, which worked great on the concrete where I usualy ran (commonly known as I-35).

I left at 4,000 rpm and it would only spin about 4 or 5 feet... probably was 60-footing somewhere in the low-1.7's....

Ran that car a LOT (maybe 50-75 times) of times like that, and the stock axles never complained. In fact, I have't seen a stock 8.75" axle break, but I know they do.... I just haven't been there for it.

This automatic car with 8"-wide tires has a fairly tight converter, and the stock 2.45 1st gear (it's not a 999.) I have a 4.10 Sure Grip final drive for it (3.55 in it right now), but I am wondering if the stock axles might not be okay, since that other set took such abuse (ALL of my racing was on brushed concrete, with much better slicks than I have now), and the "sidestep-the-clutch" driving technique I used with that ol' '64 Valiant never seemed to damage anything. This car is only about 200 pounds heavier, with a 2,500-rpm stall-speed 318 converter. If they VHT the track really well, it wouldn't slip a tire without the blower, the last time I ran it. Haven't run it blown, yet; that could change... My 60-foots were 1.91, unblown. Lookin' to improve to maybe high 1.60s-low 1.70s with the Vortech.... We'll see....

I'm on a "fixed income", and it's not "fixed" all that well; I have a spare set of stock axles that I bought out of a Pick-and-Pull, and will take them with me when I race. I think I just might get away with this, all things considered; what do you think, John? I'll be interested to see what you think about this problem.

Bill, in Conway, Arkansas

valleave(5)2.jpg
 
I use stock axles with stock wheels studs on my 73 dart sport.

340 (350+ RWHP), 3600 rpm stall converter/727 manual valve body,
3.91:1 sure grip (741) sure grip 8 3/4" rear. using 15 X 8 SBP rally wheel from wheel vintiques. Car runs low 12's (12.11 @ 111.5 mph) and has made over 250 passes the last two seasons.

Stock axles will work fine in your application. If you have SBP wheels you are happy with then use them!!

Bob
 
Like previously stated if your going to be putting any kind of "real" power to a 8 3/4 then step up to performance axles,i found that out 2 seasons ago the stock stuff WILL eventually break...
 
magicsunset08 is the moser guy on here...bought my mosers from him fully loaded for a good price and they arrived correct to my order specs and on time....his name is trevor, and for some reason people here try to discredit him, but everything turned out fine for me and the other guy that i ordered with (joint shipping to Canada)
 
I appreciate the comments from all of you folks! Thanks for the time and trouble it takes to post on here; the advice is hard to come by, anywhere else.

The stroker motor shears studs and breaks stock axles... the low 12-second car makes 250 passes with no problem with stock parts...

I am somewhere in between, probably, with a 360 that "enjoys" 10 pounds of boost from a Vortech supercharger. It's a new setup and I haven't run it on clocks, yet, but am getting really close to doing that. I would have run it at Centerville (our "local" 1,000-foot strip) Saturday night, but discovered a brake pad on my left-front K-H, "4-piston caliper" disks was dragging like crazy.... too much to try to race with, so I have a new one coming. I'll run it as soon as I get the brakes fixed.

I have no real idea how much power it might make, but I'm guessing it's going to run 12 flat (quarter-mile times) at about 114. It used to run 13.30s at 102 normally-aspirated, but since then, besides adding the blower, I went from cast iron 340 exhaust manifolds to TTI headers, and replaced a really crummy (water-heated M-P 180-degree) intake manifold with a Crosswind (Air-Gap style) intake manifold. I also added some "open exhaust" dumps to the 2.5" TTI exhaust pipes. Opening them up may help some. At some point I'll replace this 3.55 gear with a 4.10. There's a couple of tenths....

If it doesn't run somewhere around 12-flat, I'll be surprised. I DON'T think it's going to go any faster than that, although, it feels really strong... but, cars lie to you; it's really hard to tell.

95 percent of this car's life will be spent on the street. I'll run it at the strip 5 or 6 times a year, but it's not really a race car. If it were, I'd be doing a lot of things differently.

Gonna try these stock axles for a while. I WILL replace these little 7/16" wheel studs with half-inchers, if that will work with my Centerlines.

I may be sorry.... we'll see.

Thanks again fo the good info!!!

Bill, in Conway, Arkansas
 
You must log in or register to reply here.
-

Back
Top