'87 Brougham Rearend Swap.
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RWD 19xx-1984 DeVille and Fleetwood,
1985-1996 Fleetwood and Brougham Forum Discussion, '87 Brougham Rearend Swap. in Past Cadillac Vehicle Discussion; Okay, so I understand that it is possible to install the rearend of an Impala SS onto the back of ...
  1. #1
    The-Dullahan is offline Cadillac Owners Master
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    '87 Brougham Rearend Swap.

    Okay, so I understand that it is possible to install the rearend of an Impala SS onto the back of my Brougham, but that in order to do so, I would have to alter the brake system slightly, as to allow the rear disc brakes to function properly. Precisely what adjusments would have to be made?

    Likewise, what would be some other suggestible rearend swaps. The obvious is to just go with a chevy 12-bolt, I suppose, but are there any other suggestions that anyone would offer to share. Since I am going to have to swap it out anyhow, there is no reason to look into the best I can get and go for something like positraction or disc brakes.

    (Bearing in mind, this is to be used on my car after swapping the engine out for the 500 CID 1970 Eldorado motor)

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    Re: '87 Brougham Rearend Swap.

    GM didn't do any mods to let the discs work better on the SS or the 9C1, so technically, you don't have to either. You can mod the proportioning valve to put more pressure to the rears. You can also add in an adjustable prop valve to set it where you want. Mods will be needed to hook up the parking brake cables.

    I wouldn't get too hung up on the rear discs. The big drums do a great job.

    For you, going with a 500 (and a TH400, I'll guess... you better), go with any of the full size RWD 8.5 gear rear ends. Find one with 2.56s or 2.73s and you'll be perfect with the 500/Th400 combo. The SS has stock 3.08s and posi, the 9C1 axle is SLIGHTLY narrower and will have 3.08s (from an LT1 car) or 3.23s from an L99 car. Posi was OPTIONAL in cop cars (no matter what anyone tries to tell you). SPID code G80 for posi.

    Just start looking up G codes and see what the ratios are and you can quickly determine what's in a car at the junkyard when you look at the SPID.

    The 8.5" 30 spline axle (post 89) will be plenty strong for a stout 500. If you aren't going OD trans, and you probably shouldn't, you want high gears (low numerically).

    OTOH, B and D cars got the following ratios, factory, that you can look for: 2.56, 2.73, 2.93, 3.08, 3.23, 3.42, 3.73. Not all ratios came with all engines/cars/etc. If there is a specific ratio you want, I can tell you what it came in.

    Please be aware that many of the Caprice sedans from 91-96 still got the wimpy 7.5" that you already have. Make sure you can identify them.

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    The-Dullahan is offline Cadillac Owners Master
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    Re: '87 Brougham Rearend Swap.

    ^That about sums up all the information I need. Sadly, I will have to use other methods, as the junkyard here is utter rubbish.

    ----------

    Oh, an I am still highly considering utilizing the 4L80e Transmission, actually.

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    outsider is online now Cadillac Owners Connoisseur
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    Re: '87 Brougham Rearend Swap.

    what would be needed to put the rear end from a 95 fleetwood brougham into an 87 brougham? Just out of curiousity

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    Re: '87 Brougham Rearend Swap.

    Not much. I can't remember the length difference between the TH200-4R and the 4L60E, so you'll need to look them up to figure out what driveshaft will fit. Grab the 95 for sure, just in case. Also, get the rear sway bar and hardware if bigger than yours (it likely is). A socket set (impact is much better), a line wrench, a couple of open end wrenches, a pry bar. Pop the old lugs out of the 87 axles (or buy new ones) and put them in the 95 axles. The size is different.

    I suppose I could just bring you the rear and driveshaft from my parts car in the spring. I kind of want to keep it a roller for ease of movement, but for a buddy, I would grab it. I think I have the sway bar around here somewhere. If I have an extra, I can bring that, too. I need one for my 81. It has 2.93s. I have to deliver some seats down your way. Meet in North Conway? Of course, don't hesitate to grab something local. Jim will have stuff for you, too.

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    Re: '87 Brougham Rearend Swap.

    I don't think any factory driveshaft will fit and I will thereby just have to shorten my own. Remember - I have a Commercial Chassis, not a standard Sedan. Also, the 4l80e has OD. I would prefer the strongest rearend I can get. I will have to see what's for sale on CL.

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    outsider is online now Cadillac Owners Connoisseur
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    Re: '87 Brougham Rearend Swap.

    I was wondering because I might retire my 95 next year and swap the drive train into my 87. The 95's frame and underside is getting pretty rusty. During inspection they found a rust hole under the passenger rear floor which I've patched with some sheet metal and fiberglass for now but while I was under there I was noticing that the frame isn't very pretty.

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    Re: '87 Brougham Rearend Swap.

    How well do you think I could get a 3:42 rear end from a late 90's Suburban to work, if coupled with the 4l80e? Though it is a higher geared, I would think it could stand up to the engine/trans combo, no?

    I figured I should ask. It sort of popped up in conversation, as someone I know has access to one that's just sort of sitting around, but apparently in excellent shape.

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    Re: '87 Brougham Rearend Swap.

    3.42s are an excellent choice. However, that rear won't bolt in your car. The carrier and gears will bolt in an 8.5 rear from a B or D body, though (if the Burb has an 8.5 rear).

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    The-Dullahan is offline Cadillac Owners Master
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    Re: '87 Brougham Rearend Swap.

    ^That is precisely what I was curious about.

    However, I will have to get an answer back from the present holder of said equipment, as I currently know very little about it.

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    Re: '87 Brougham Rearend Swap.

    I thought the 90s Fleetwood and SS have a completely different rear end size then the older ones, if so you'd probably need a different length driveshaft. And both those cars also have a different transmission then yours, so the driveshaft from them probably won't work either.

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    I know I need a new driveshaft. I will see if I can just get mine shortened, since the transmission mandates a shorter one. If not, I will need a custom one to be made. My Brougham is a little bigger than most of yours.

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    The-Dullahan is offline Cadillac Owners Master
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    Re: '87 Brougham Rearend Swap.

    And I'm back. Been browsing Craigslist for various things that interest me (For a multitude of vehicles and non-vehicles)

    This has caught my eye. As far as I am aware, this should be compatible with my car (Though I am not entirely certain if the upper and lower arms are?)

    http://cfl.craigslist.org/pts/3522043349.html

    Questions, comments concerns?

    I have been tremendously busy, but will have a bit of free time here and there over the upcoming weeks and am hoping to grab some items for my Cadillac while I have the opportunity. Still planning to go with a 4l80e Transmission at this point.

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    Re: '87 Brougham Rearend Swap.

    The answer is... maybe. If it is a 77-up rear, not if it's a 76 and earlier. However, the early ten bolt isn't as strong. It's an 8.2" ring gear, and it has less splines (28 vs 30 on the later 8.5). Keep shopping for the later 30 spline 8.5". Also, the 2.73 isn't a great choice for an OD trans, you'll want at least 3.08s.

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    The-Dullahan is offline Cadillac Owners Master
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    Re: '87 Brougham Rearend Swap.

    That was why I posted. Wasn't sure if anyone here could identify the year, as their lack of pictures and information didn't help any.

    Since no one sells their rear ends on Craigslist by their technical information and instead sells them by what type of vehicle they came out of, is there a specific series of cars I should look for parts from? Even if the rearends were only optional or varied by year, I feel I could find a good swap much quicker if I knew where it was coming from.

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