Rear Disc Brake Axle Swap

IF YOU HAVE QUESTIONS ON THE REAR DRIVE SHAFT OR AXLE, IT GOES HERE.
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socalastro
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Rear Disc Brake Axle Swap

Post by socalastro »

Howdy. Got a question. Are there any rear axles out there that I can directly swap into my 97 LS 2wd that have disc brakes? My rearend began howling a couple days ago and I figured that if a rear disc axle was available, this would be the time to do it. If not, any suggestions on what most commonly goes wrong with these rearends? Mine is a 3.73 (GT4) and the van has 174,000 miles. The original owner says he did not repair or replace the rearend. (0 miles to 151,000 miles). I have had it 10 months and driven it 23,000 miles with no issues. Thanks for your help! Chris.

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Re: Rear Disc Brake Axle Swap

Post by LiftedAWDAstro »

No direct swap. Usually the pinion bearings are the first to go. If you get it fixed ASAP you probably won't need to replace the gears. Won't know until it's opened up though.
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Re: Rear Disc Brake Axle Swap

Post by 97CargoCrawler »

I may be interested in this swap too in my '97 2WD. Lifted, do you know off the top what the differences might be? (6 lug, as opposed to 5, etc.)

I think I'd like to buy an axle, rebuild it with a locker and 4.10 gears and then install it. I need my van for work so I can't pull the axle on it and do all this in a weekend. So I figure I might as well buy and upgrade then swap.

Thanks!
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Re: Rear Disc Brake Axle Swap

Post by LiftedAWDAstro »

Without doing a custom GM 12 bolt like smiliesafari did or a Ford 9" like Peter did, Your best bet is stick with the stock axle and upgrade the rear brakes to the 11" drums, put in the locker/posi and gears of choice. Another possible option might be an axle from a G20 van. Not sure if they used an 8.5" 10 bolt or a 9.5" 14 bolt like the SS454's used. There are both 5 lug axles.
Current rides:
2013 Toyota Tundra DC 4x4
2008 Dodge Nitro 4x4
2005 Nissan Sentra 1.8S Special Edition

Mileage spreadsheet

Vans owned:
1986 Safari 2.5L 4 speed manual - scrapped
1995 Astro 2WD conversion 4.11 posi, shift kit, DHC rock rails - sold to Skippy
1998 Astro 4x4 D44, D60, NP231, full hydraulic system with 9k# Milemarker winch and snow plow - sold to Lockdoc
2003 Astro AWD all stock - traded for a 3/4 ton truck
2005 AWD, 4.10's - sold to skippy

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Re: Rear Disc Brake Axle Swap

Post by 97CargoCrawler »

Hmmm. I figured I could use a late model Astro/Safari axle with disc brakes and just need to maybe fab up a new brake line or something simple like that. #-o

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Re: Rear Disc Brake Axle Swap

Post by LiftedAWDAstro »

Well, you could but in order to get factory disc brakes you'll have to get a 2003 - 2005 axle and they run a 6 lug pattern. You could always redrill the axles and discs and run the same 5 lug pattern you have now.
Current rides:
2013 Toyota Tundra DC 4x4
2008 Dodge Nitro 4x4
2005 Nissan Sentra 1.8S Special Edition

Mileage spreadsheet

Vans owned:
1986 Safari 2.5L 4 speed manual - scrapped
1995 Astro 2WD conversion 4.11 posi, shift kit, DHC rock rails - sold to Skippy
1998 Astro 4x4 D44, D60, NP231, full hydraulic system with 9k# Milemarker winch and snow plow - sold to Lockdoc
2003 Astro AWD all stock - traded for a 3/4 ton truck
2005 AWD, 4.10's - sold to skippy

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Re: Rear Disc Brake Axle Swap

Post by 97CargoCrawler »

I actually want the 6x5.5 pattern because it's the same as my FJ40 Land Cruiser. Then I can swap wheels back and forth! :muhaha:

:cheers:
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Re: Rear Disc Brake Axle Swap

Post by akforceten »

There are many rear ends out there with disc brakes on them which ones fit I don't know . If you end up putting in the same rear end I found this the other night . I have used there kit for the D 60 an it was great ,so I don't know about there astro kit.

here is the link http://www.tsmmfg.com/2183.htm
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1997 RWD Astro

1995 GMC Safari 4x4 lifted 5"

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Re: Rear Disc Brake Axle Swap

Post by 97CargoCrawler »

Oh wow! I'm putting a kit very similar to that on my FJ40. I know people who have this type of kit and love them. I didn't know anyone made it for the Stro! Looks to be a much cheaper option that fitting a new axle. I wish the caliper with parking brake wasn't $180 more than the non park option. Thank you for this info! This might actually be a much more viable option for me.

:cheers:
1997 SAFARI 2WD CARGO
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"I do not think there is any thrill that can go through the human heart like that felt by the inventor as he sees some creation of the brain unfolding to success... Such emotions make a man forget food, sleep, friends, love, everything." Nikola Tesla

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Re: Rear Disc Brake Axle Swap

Post by brokenwrench »

socalastro wrote:Howdy. Got a question. Are there any rear axles out there that I can directly swap into my 97 LS 2wd that have disc brakes? My rearend began howling a couple days ago and I figured that if a rear disc axle was available, this would be the time to do it. If not, any suggestions on what most commonly goes wrong with these rearends? Mine is a 3.73 (GT4) and the van has 174,000 miles. The original owner says he did not repair or replace the rearend. (0 miles to 151,000 miles). I have had it 10 months and driven it 23,000 miles with no issues. Thanks for your help! Chris.

Any 2003 to 2005 axle will come with disc brakes, it will also have 6 on 5 inch bolt pattern so you will have to use rims from that era or get the axles redrilled to 5 on 5. your transmission should have the VSS tailshaft so your ABS should be unaffected. many drivers unhook the ABS after they have the slid through the intersection experience on dry pavement. there may be a difference in residual pressures in the master cylinder between the disc drum cylinder and disc disc cylinder, you may need a pressure differential valve in series with the main line going to the rear brakes, these go on with the usual brake compression fittings and cost from $30 to $50. (proportioning valve) alternately you could take the master setup off the van you get the rearend from.

with daily driving you will not notice much difference with rear discs. they are useful if you do towing. the rear brakes do about 20% of braking in usual conditions. if you do a lot of mountains where there is prolonged brake application, they have more utility. i see lots of people spend huge money on huge disc brakes front and rear and they are surprised that they make little difference with the usual street tires. ironically, the better your front brakes work, the less your rear brakes gain adhesion. many gains can be had by putting good shocks on the front so that you minimize "braking dive" and then minimize weight transfer bias back to front, and refreshing the front brakes. rear discs sound like a great option, they are cleaner and easier to service but ultimately your overall braking is determined by the relationship of your tires going slower than the road. factory setups are designed to that all brakes can lock and ABS then controls that. "bigger" brakes decrease the time interval of beginning brake application to maximum adhesion but do not increase maximum adhesion. however, the rear brakes always run significantly cooler as their application is delayed in normal braking so for a maximum single braking effort, they are never at their best. they need to be warmed up, and keep warm, this is why racers use them on track racing.

if you want to decrease your "panic stop" distance, you need to increase adhesion, i.e., wider tire, taller tire, or stickier compound.
Last edited by LiftedAWDAstro on Thu Nov 24, 2011 8:57 am, edited 1 time in total.
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Re: Rear Disc Brake Axle Swap

Post by MountainManJoe »

brokenwrench wrote:with daily driving you will not notice much difference with rear discs.
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Re: Rear Disc Brake Axle Swap

Post by doyoulikeithere »

I've bled my ABS brakes lots of times.
I used a 8 or 10 MM flare wrench.
Works Fine.
Cost 5.99.
:-k
Last edited by LiftedAWDAstro on Thu Nov 24, 2011 9:00 am, edited 1 time in total.
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Re: Rear Disc Brake Axle Swap

Post by 97CargoCrawler »

Yeah, you can usually get by with removing a rear cylinder/caliper and not loose enough fluid to get air into the ABS unit. But as soon as you get into pulling the ABS or adding in proportioning valves, I think you might have some problems there. :-k
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Re: Rear Disc Brake Axle Swap

Post by Smiliesafari »

For the time and money the 11" drum conversion is a much better investment. You don't have to work with proportioning valves or master cylinders. Neither the drum or disc conversion will make your van stop like a formula one car. These vans weigh 4000 pounds. The best tip: "drive accordingly".
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