Slant Six Forum
https://www.slantsix.org/forum/

1972 Valiant 8 3/4 Rear Swap
https://www.slantsix.org/forum/viewtopic.php?t=30662		 Page 1 of 1
Author:  Hyper72Valiant [ Thu Aug 21, 2008 12:13 am ]
Post subject:  1972 Valiant 8 3/4 Rear Swap
Hey guys, I have not been on in about 2 years, was on an LDS Mission in NY....anyways, now I am back! I forgot a lot about what I needed for my '72 Valiant to swap in an 8 3/4. I have some parts, but, don't know what all I need I guess. I need to get this swapped in soon because I just got my car inspected/emissions crud done and my car barely passes on the rear brakes, minimum is 1 and I had 2 (mm's I assume). Anyways, I would rather not spend money on repairing the 7 1/4 brakes and just spend money on putting on the 8 3/4....

Ok, here are the parts I have:

-8 3/4 A-Body Width Housing
-11" Backing Plates Attached to housing, but, have 10" Backing Plates to put on
-8 3/4 3.55 Sure Grip 489 Case
-8 3/4 Shock Plates and U-Bolts
-8 3/4 Axles (I think they are A Body Axles...they don't taper and from bearing retainer (I think it's called) to Spline edge was 25.5", I think I read it should be 26", maybe I measured wrong)

That's all I have in my garage, what parts do I need to complete this install? What seals, gaskets, bearings, lube, etc... Can I use any parts from my 7 1/4 that is currently on the car?

I will be swapping on a front disk brake conversion at the same time most likely and have all the parts for that I think based upon: http://www.bigblockdart.com/techpages/d ... sion.shtml

Car is stock...will be modified in the future for lot's of Horsepower and Torque, decided would be "sick" to have a hopped up and fast /6 rather than a V8, PLEASE tell me guys what I need to do, THANKS in advance and if there are other posts that answer my questions, sorry.
Author:  Doc [ Thu Aug 21, 2008 10:47 am ]
Post subject: 
Do you have the brake "hard lines", junction block, flex hose and vent?
How about all the brake springs and hardware?
Is the plan to cut your current driveshaft to fit?
DD
Author:  Hyper72Valiant [ Fri Aug 22, 2008 12:35 am ]
Post subject: 
Hey Doc, I am sorry if I sound stupid at all....do I need to get different brake lines then I have already on the car? 9" drum all around.
Do I need both a junction block and a proportiong valve? No, I don't have the brake springs or hardware, where can I get all of that, altogether preferably? I forgot I have Parking brake levers and struts (I think they are for 10" brakes, how would I know?) I could cut my driveshaft, but, if it's a bit rusty I might go find another one off of a junk car with 8 3/4 or buy a new one.
Author:  Hyper72Valiant [ Fri Aug 22, 2008 12:35 am ]
Post subject: 
Sorry also, I don't know what a vent is...?
Author:  Hyper72Valiant [ Wed Aug 27, 2008 2:10 pm ]
Post subject: 
Haha, k, guess I am on my own...
Author:  Pierre [ Wed Aug 27, 2008 4:23 pm ]
Post subject: 
The screw that holds the junction block to the axle tube - its not a traditional bolt. It has a hole in it and spring loaded cap on top to let the housing breath without letting stuff get in.

Here you go. They are (or at least were) also available from the dealer.
Author:  Doc [ Wed Aug 27, 2008 4:30 pm ]
Post subject: 
You should get some new hard lines (brake lines) because the ones off the 7 1/4 will be a little short.
Your e-brake cables will swap over but some of the brake hardware will take effort to find. You may want to see if you can get all the brake stuff off a wrecking yard car, truck or van.
DD
Author:  Hyper72Valiant [ Thu Aug 28, 2008 10:03 pm ]
Post subject: 
Hey, thx Doc and Pierre! I looked at my rearend (not the one attached to my body...) and it actually does have on it the vent with the spring loaded screw :) So, I think I will take it off and look at it and see if it is ok. Also, it has hard lines connected to it going from it to both backing plates :) Ya, I do want new hard lines anyways cuz the ones on the car are pretty rusted out, I think I will just go OEM, stainless steele I was told is known to leak a bit...is there a coating to put on the OEM brake lines to make them not rust? I am actually buying a lot of stuff for my rearend and some other things I need for my front disk conversion from Moparts. There deals seem good if not cheaper and I am getting some kits from them. Really nice guy, talked to him for over an hour today about what I would need and he was a great help, his name is Scott.

Well, thx, will let you know how it goes! Will take some pics too for those interested.
Author:  bmimken [ Sat Aug 30, 2008 5:37 pm ]
Post subject: 
Hi, I just did this swap earlier in the year.

A couple things...first, you will definitely need to shorten your driveshaft (mine was very rusty as well, but the shop actually cleaned it up pretty good when they shortened it),
Second, the 10" brakes could be a headache. Make sure you have the small bolt pattern 10" backing plates and not the large bolt pattern ones. There IS A DIFFERENCE between them and they do not mix and match. You are also going to need the SBP drums and shoes. They are like a good 1/2"-1" narrower than the LBP ones.
Feel free to pm or email me if you have any more questions.

Brian[/u]
Author:  Hyper72Valiant [ Sun Aug 31, 2008 8:32 am ]
Post subject: 
Ya, I was thinking about where I was going to get that shortened? Just any machine shop or do I need to find a driveshaft shop or something? If they cleaned yours up pretty good, then, I should just give them the one on my car and have them work on it :) As for the brakes, I was talking with this guy from Moparts named Scott and told him I already had 10" backing plates and he said the same thing...so, I am going to buy the backing plates that come with his 8 3/4 Master Brake Install Kit, so, good there. I will just put the backing plates I have on Ebay, someone could use them. I am moving up to LBP on front and back and the kit for the 8 3/4 makes it so, I am just using the A-body LBP axles I have in my garage, but, putting on them Green Bearings and new seals and gaskets. Thx bmimken, I will let you know whats up.
Author:  bmimken [ Sun Aug 31, 2008 3:37 pm ]
Post subject: 
I went to a guy who specialized in driveshafts nearby where I live. Found him from another member on the board. I also had the u-joints replaced at the same time.
Good luck.

Brian
Page 1 of 1 All times are UTC-07:00
Powered by phpBB® Forum Software © phpBB Limited
https://www.phpbb.com/