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Axle swap questions?


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#1 offroader461

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Posted 03 May 2007 - 01:57 AM

i am going to pick up my 8.8 this friday and plan to swap it in this weekend....what i need help on is the following...

1. Any brake modifications necessary? bigger master cylinder..different proportioning valve etc. axle will have disk brakes
2. Does it matter that the pinion is offset more than the D35...found a site that states that it is...i should just line everything up and weld away
3. How hard is it to swap it in

i have read a lot of posts about it but still confused a little bit on what to do and how to do it....thx for all the help..wanna do it right the first time lol
1987 Comanche Chief--4x4..4.0L pooguet, NP231, D30/D44 4.10's Locked F/R 7.5" RE front lift and SOA rear 33" BFG's, 40series flowmaster, AiRaid...yada yada yada
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#2 88swampedmj

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Posted 03 May 2007 - 02:19 AM

iam no expert but i have put an 8.8 under my truck recently,
i basically swapped it in, it bolted in pretty easily. i havent done the brakes yet but iam not using any different master cylinder or prop. valves.. i bypassed the valve on the back and iam just running hard lines pretty much.

'88 comanche 4.0 5spd sb 2wd DD 


#3 Rokhound

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Posted 03 May 2007 - 06:05 AM

i think from what i have read to do the brakes you will need (2) right hand side brake lines some steel line and a 3 way T for the brake lines to run to. The next question are you going SOA if so you are going to need to get a longer brake line that comes from the truck down to the axle (mid 90's dokata rear brake line) If you are going SOA you would want to set your pinion up to spec or close to it. If your going SUA the same as you D35 then I would take the specs from the D35 and copy it to the 8.8. Now I am not sure that this is right as I have not put mine in but this is how i am going to do it. Also make sure you get the flange for the drive shaft and some spacers for the wheel and I think you good to go.

I have that Ford Ranger so I am going to check and see if that flange will match our drive shaft u-joint so more on this later

#4 87manche

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Posted 03 May 2007 - 08:41 AM

spicer part number is
2-2-1379
that's the 1310 flange adapter.
Pinion length is a little longer on the 8.8 with the flange adapter, so you'll have to be lifted a few inches or shorten the driveshaft.

Brakes:
I plan on attempting it witl the stock master/propo valve.
If it doesn't work I'll remove the spring and o ring from the propo valve.
If that doesn't work I'll go get a ZJ valve, cause they had discs from the factory.

You will need spacers in the rear if you want to run stock wheels.

Don't worry about the offset, that's a problem for wranglers because they have such a short driveshaft. Since our driveshaft is 6 feet long it's not an issue.

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#5 pingpong

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Posted 03 May 2007 - 10:59 AM

Here are the linke I used when I did the swap on Pong a while back, before I decided to go 1 ton

http://www.jedi.com/...eep/ford88.html


this pretty much covers everything.


I eventually ended up doing the XJ prop valve, and that was only cause when we back halved my rig the line broke
90 MJ Atleast that is what it was.

87 XJ chopped and locked.... and ready for the rocks

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#6 Eagle

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Posted 03 May 2007 - 04:06 PM

There's a good chance the stock master cylinder won't hold or push enough fluid for the rear disc brakes. Best swap is to use both the master cylinder and proportioning valve from a mid-90s ZJ with rear discs.
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#7 offroader461

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Posted 03 May 2007 - 06:23 PM

sry i forgot to spec my truck for you guys so you know what I'm working with....

it has 3" rough country coils and ACOS up front for a total of about 4" and a 3" AAL in the back already, extended skyjacker stainless brake lines...and I'm planing on going SOA

will my extended brake line i already have still work or should i get the dakota one, also i was planning on using the ZJ master cylinder along with the proportioning valve...thx for all the help so far..its answering alot of my questions about this swap
1987 Comanche Chief--4x4..4.0L pooguet, NP231, D30/D44 4.10's Locked F/R 7.5" RE front lift and SOA rear 33" BFG's, 40series flowmaster, AiRaid...yada yada yada
**** _______
_____| |__,\__\,____
l_---\__|___l---[]lllllll[]
_(o)_)_____(o)_)--o-)_)

Project-->THE CHIEF


"Its a Jeep thing..i still don't understand!"

#8 pingpong

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Posted 03 May 2007 - 10:53 PM

Just have a custom SS one made. It will save you the time and money in the long run. I think my custom 36" for the rear was like 54 bucks a year and a half ago
90 MJ Atleast that is what it was.

87 XJ chopped and locked.... and ready for the rocks

http://mpjai.com/phpBB2/index.php

http://community.web...om/user/cj7xjmj

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#9 offroader461

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Posted 07 May 2007 - 12:03 AM

well i picked up the axle but didnt have time to install it...what is the angle that i should set my pinion at...should i point it at the t/c or just set it to what my D35 is at now?? unfortunantly i might just keep the truck SUA b/c i don't have the funds to lift the front to match right now...dunno havent decided yet...but will this make a difference in setting the angle....thx
1987 Comanche Chief--4x4..4.0L pooguet, NP231, D30/D44 4.10's Locked F/R 7.5" RE front lift and SOA rear 33" BFG's, 40series flowmaster, AiRaid...yada yada yada
**** _______
_____| |__,\__\,____
l_---\__|___l---[]lllllll[]
_(o)_)_____(o)_)--o-)_)

Project-->THE CHIEF


"Its a Jeep thing..i still don't understand!"

#10 JOMJ87

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Posted 07 May 2007 - 12:24 AM

You should set it close to parrallel with the Tcase output I think 1-2* lower is what is usally recomended. Unless you have a SYE then right at it. yopu can make the angle on you D35 to it and it will be fine. I will tell you that going SUA with a 8.8 will lower your truck a smudge from stock. The axle tube are bigger diameter thus they act like it has blocks on it. it want be to much though. Hope that helps.

Cole
87 MJ / SOA rear and 7.5"ish front, Locked Front, D44 Rear, 35 BFG MTs, TJ fender flares And alot of work to be done

#11 offroader461

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Posted 07 May 2007 - 12:27 AM

i would prefer to go SOA so i might wait on installing it when i can get the front to match...that helps out alot tho
1987 Comanche Chief--4x4..4.0L pooguet, NP231, D30/D44 4.10's Locked F/R 7.5" RE front lift and SOA rear 33" BFG's, 40series flowmaster, AiRaid...yada yada yada
**** _______
_____| |__,\__\,____
l_---\__|___l---[]lllllll[]
_(o)_)_____(o)_)--o-)_)

Project-->THE CHIEF


"Its a Jeep thing..i still don't understand!"

#12 minydigger

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Posted 07 May 2007 - 08:19 AM

If you want to go ahead and SOA the rear but not not go any higher pick up a set of wagoneer rear leafs, they are the same dimensions as MJ springs but are flatter. Then when you get the money to go higher in the front you can put the stock springs back in. This is what I did on my truck and it worked out well.
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#13 88MJay

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Posted 07 May 2007 - 08:34 AM

How much height would one lose by using waggy springs instead of MJ springs on a SOA?