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Ford 8.8 swap again....i know srry

9

93xj-jeeper

NAXJA Forum User
Location
Pacific Northwest
hey guys, i definately did search this quite a bit and found a lot of good information but couldnt find out exactly what i was looking for.

I'm saving up for lift to run 33s and am worried about my 27 spline 8.25 out of my 93 and also my brakes so i am thinking about swaping in a 8.8 out of a junkyard from a newer (95 and up) explorer with disc brakes.

Basically what i am trying to find out is.....for those of you who have done the swap how much better are your brakes with the disc brakes. This is one of the main reasons i would like to do the swap. I have 31s right now (non abs) and frankly my brakes arnt very good right now and they're bled, new calipers, rotors, etc. So I am worried moving up to 33s my brakes will suck.

Also, what all do you have to do to switch over to the disc brakes with the 8.8. Just new lines (which ones?) or do i need like a new master cylinder or anything?

Lastly, I have read some stuff about the pumpkin being off-center in the 8.8. Does that seem to be a problem at all?

Thanks a lot for your help guys, srry about the long post.
 
if you do a search with my name in it you should come up with the info you need on the brakes i replied to many posts.

but in a nut shell if you use two pass side explorer lines and connect them with hard line to your t-fitting u currently have it will all go together nicely. the fittings are the same size :)

the best way i can describe the benifit of the disks is like when you just adjust your rear star nuts out and the breaks grab nice for the first few days. well it's like that all the time with disks.
I have not done any mods to the master cylinder but i do have a 96 which has the dual diaphram booster which most people say is a huge improvement over the later model boosters. i did take the valve out of the prop valve so the brakes get equal pressure all the time but this only changes the braking under heavy pressure.
the real improvement in breaking capibility will be if you do something to the front seeing as that is where most of your breaking power comes from. also it is nice to not have to remove the drums every time you go thru deep mud to clean them.

as for the pumpkin being off center... mine does not give me any vibes but i do have a sye which lengthened my drive line making the angle much less
o yea i run 33's on my setup and the breaking not perfect but the only thing that will make it better is different front breaks.
pm me if you have any other q's
 
I have no vibes either, without an SYE. Also I used rear rubber lines from my ZJ that I had laying around, worked perfect. I haven't gotten around to removing my proportioning valve, but it still brakes very well without that mod.
 
I did this swap last weekend and am going to go to the junkyard to find a prop valve from a 4-disc grand cherokee. The braking is great with the 8.8, when I get pressure. But about half the time I hit the brakes I get nothing, pump it twice and it brakes good.
 
I'm gonna ask an 8.8 question on this thread so i dont have to start a new one... Will it be wide enough to simply run with stock rims on 31x10.5 tires? It won't be so narrow that they rub on leaf springs, right?
 
Keep the 8.25

I am a firm believer in if it isnt broke...dont fix it. I have an 8.25 in a 4000 pound 1964 dodge truck with a very well built 440 ci big block in it.. I have a bigger rear at home ready to go in it...but I have yet to break this one. The truck will run high 13s all day at the track..and when I am driving it....I am very hard on teh drivetrain. I cannot break this rear! I am not saying that you wont.....but......my philosophy is when it starts making noise...then change it. Until then....I will let you know when I break mine
 
C85D4x4 said:
Is the 8.8 a direct swap?
What years should i be looking for?
Click to expand...

NOPE. Spring perches, shock mounts, and driveline flange all needs to be addressed. Possible address for the drum to caliper conversion as far as brake lines.
 
I don't know about cherokee's (yet) but ALL VW's have a bias of 80% front brakes 20% rear brakes doing the work.. that's on FWD so take it for what it's worth.. I'm sure it's similar though..

So lets say you increased the Swept Area of the rear brakes by 20%

so you have increased the Total braking power by 20% of 20% or 4% total

So you went from 80/20 split to an 76/24 split...

This would help with excessive nose dive on a lift with bigger tires and should help keep the truck straight when braking hard..


So lets say you increase the rear swept area by 50%

50% of 20% is 10% total or a 70/30 split...

However.....

a 4-10% is a negligable increase overall... and I REALLY doubt there is a 50% difference in swept area between the 8.8 discs and the Stock Kee drums.. probably more like 10-20% increase.....if any at all..

I'd see if there is anything you can do for better brakepad compunds in the stock front and rear...

Look for something with a quick heatup and high initial grip..... On my VW's I get autoX pads to provide MUCH better stopping power on the stock brakes. Get them front and rear and maintain the front to rear bias while gaining some more stopping power at both ends... the pads are dusty as hell and they wear out quickly... but the increase in stopping power is well worth it on the track and in emergency stops.

If you go with the 8.8, go for it after youve killed your Chryco 8.25 or it starts making noise... or if you just want some beef for wheeling to prevent a failure..

I just don't forsee the discs making enough of a difference alone to offset the 33's increased leverage on your brakes...
 
Citat3962 said:
I don't know about cherokee's (yet) but ALL VW's have a bias of 80% front brakes 20% rear brakes doing the work.. that's on FWD so take it for what it's worth.. I'm sure it's similar though..

So lets say you increased the Swept Area of the rear brakes by 20%

so you have increased the Total braking power by 20% of 20% or 4% total

So you went from 80/20 split to an 76/24 split...

This would help with excessive nose dive on a lift with bigger tires and should help keep the truck straight when braking hard..


So lets say you increase the rear swept area by 50%

50% of 20% is 10% total or a 70/30 split...

However.....

a 4-10% is a negligable increase overall... and I REALLY doubt there is a 50% difference in swept area between the 8.8 discs and the Stock Kee drums.. probably more like 10-20% increase.....if any at all..

I'd see if there is anything you can do for better brakepad compunds in the stock front and rear...

Look for something with a quick heatup and high initial grip..... On my VW's I get autoX pads to provide MUCH better stopping power on the stock brakes. Get them front and rear and maintain the front to rear bias while gaining some more stopping power at both ends... the pads are dusty as hell and they wear out quickly... but the increase in stopping power is well worth it on the track and in emergency stops.

If you go with the 8.8, go for it after youve killed your Chryco 8.25 or it starts making noise... or if you just want some beef for wheeling to prevent a failure..

I just don't forsee the discs making enough of a difference alone to offset the 33's increased leverage on your brakes...
Click to expand...

not to be an donkey but sometimes paper doesnt show what happens in the real world. i dont' think that all the people that have done the 8.8 swap are lying about the breaking ability of there new breaks.

sixshooter said:
I am a firm believer in if it isnt broke...dont fix it. I have an 8.25 in a 4000 pound 1964 dodge truck with a very well built 440 ci big block in it.. I have a bigger rear at home ready to go in it...but I have yet to break this one. The truck will run high 13s all day at the track..and when I am driving it....I am very hard on teh drivetrain. I cannot break this rear! I am not saying that you wont.....but......my philosophy is when it starts making noise...then change it. Until then....I will let you know when I break mine
Click to expand...

on the flip side of this oppinion there are the people that want to upgrade before it breaks on the trail leaving you stuck where you dont want to be. it is one thing to break on the road or on the strip where a tow truck can pick you up and take you home but there are verrrrry few tow trucks that go rock crawlin to pull you butt out. and the differences between the beating on your truck on the street and even at the strip pail in compairison to playing in the rocks in a situation with only one wheel getting 100% of the vehicles torque while gaining/loosing traction violently on a rock surface. if you dont' beleive me watch some vid's /pics of people snaping 14bolts on pbb. and then go and find a few people that snap them beating on there truck on the road.
 
Last edited:
bj-666 said:
on the flip side of this oppinion there are the people that want to upgrade before it breaks on the trail leaving you stuck where you dont want to be. it is one thing to break on the road or on the strip where a tow truck can pick you up and take you home but there are verrrrry few tow trucks that go rock crawlin to pull you butt out. and the differences between the beating on your truck on the street and even at the strip pail in compairison to playing in the rocks in a situation with only one wheel getting 100% of the vehicles torque while gaining/loosing traction violently on a rock surface. if you dont' beleive me watch some vid's /pics of people snaping 14bolts on pbb. and then go and find a few people that snap them beating on there truck on the road.
Click to expand...

My only opinion I guess I feel that the 8.25 takes more abuse verbally than it should. I have been running these in trucks and cars for a long time and I think unless the vehicle is doing really agressive crawling or running a locker with giant meats......you dont necessarily need to change the rear. He stated that he wants to run 33s on his jeep....The 8.25 should be plenty strong enough for those. I fully understand the difference between asphalt and rocks....I have played on both...but, even a 4.0 in low range on the rocks is still puting minimally more comparable force on a rear than a 400+ horse full size with a locker and slicks. If he doesnt need teh rear, again my opinion, I would rather see skid plates or unibody reinforcement. again my 2 cents.
 
Citat3962 said:
I just don't forsee the discs making enough of a difference alone to offset the 33's increased leverage on your brakes...
Click to expand...

Don't believe this pencil pusher! Masturbation doesn’t look good on paper either but when you do it……

The discs make a HUGE difference. I have 33s and I NEED the braking power and to be honest, I could use MORE! Try backing down a steep grade with drums and 33s. It is a disaster. I had 31s on the 8.8 and it stopped pretty well. Now with the 33s it is harder to stop. The discs make a world of difference! Ask yourself a question, if this didn’t make a difference than why do they put 4 wheel discs on a lot of other vehicles OEM? THERE IS A DIFFERENCE!

I have had the 8.8 for a little while now and I LOVE IT. I did all the work myself and it was too easy. Just cut off all the old mounts and weld on some new pads and shock mounts, do up the brake lines and you are there. Make sure you get your driveline angle set up for the lift you are anticipating or you will have to either re-do it or use shims.

Being offset has only caused me one problem. I crunched my muffler when I was krawling on the first ride with the 8.8. I got a new, shorter muffler and it has been perfect.

I agree with the double pump sometimes to get full power though, a little short fall but we all made compromises when we got into this XJ thing. I haven’t tried the prop valve from a 4-disc Grand Cherokee yet but will look into it as a future possible mod.

I have NO vibrations and have the SYE and the CV driveshaft.

DO IT! It is a fun project and an HUGE improvement.

PM me with your e-mail and I will send you some pics.

Cracker
 
ya...that is one of the main reasons i want to do the swap like bj-666 said:

"on the flip side of this oppinion there are the people that want to upgrade before it breaks on the trail leaving you stuck where you dont want to be. it is one thing to break on the road or on the strip where a tow truck can pick you up and take you home but there are verrrrry few tow trucks that go rock crawlin to pull you butt out"

I dont want to be on the trail and have my 8.25 break leaving me stranded. And around where i wheel if you are forced to leave a vehicle the night...it probably wont look the same the next day!

Also, what spline is your 8.25 sixshooter? Because i only have the 27 spline, and it seems to me that breakage is very possible in 4 low, 33s, regeared, and especially a locker.

Besides, like cracker was saying. I need better brakes. my brakes with 31s are marginal at best. With 33s, id be pretty worried about them, especially when creeping down a steep decent with a ledge and trying to slowly come off of it. I just dont know how that would work with the drums. Every little bit of braking power helps.
 
cracker said:
I agree with the double pump sometimes to get full power though, a little short fall but we all made compromises when we got into this XJ thing. I haven’t tried the prop valve from a 4-disc Grand Cherokee yet but will look into it as a future possible mod.
Click to expand...

^^^ So you're saying it's given a mushy pedal feel that sometimes requires multiple pumps to compress the brakes??? sounds like a downgrade! I think you might need an adjustable proportioning valve like a willwood or brembo.. that or possibly the stock prop valve from the Explorer the 8.8 came off of..

I would not do this swap unless the proportioning was sorted..

My bad... didn't mean to come off as though I was saying NOT to get the 8.8..

More the point I was trying to make was... why spend 3-500$ swapping to a bigger rear axle when you could spend 75$ on new pads all the way around and get similar results...

Or better yet do the axle swap, get the discs, and some nice grippy pads and be 2 steps ahead of the game... Just be aware of all your options..

Trust me the more research into the different axles I do the more attractive the 8.8 swap looks...

I'd do it purely for the sake of working on disc brakes instead of drums..
 
the prop valve does not make you pedal feel squishy it is the master cylinder/ air in lines if the master cannot move enough fluid you will have to push the pedal quite a ways to get enough to both front and rear brakes sometimes causing you to "double pump" the breaks i beleive 96 and newer dont' have this prob because of a different master and vacume assist. the prop valve on a stock jeep gives you 50/50 breaking unless you realy mash the breaks then it gives the front more beacaue that is where the weight of the vehicle is transfered giving this area more breaking ability. i took my prop valve out so on steep decents i have 50/50 breaking all the time which is great when you have to back down in a steep situation. but not so great when you slam on the breaks at highway speed because all wheels get equal pressure causing the rears to lock up before the front which can be fun to say the least.
 
Citat3962 said:
More the point I was trying to make was... why spend 3-500$ swapping to a bigger rear axle when you could spend 75$ on new pads all the way around and get similar results...
Click to expand...

I'm pretty sure that most people, including I, did the swap for the 8.8's huge strength upgrade over a stock axle. The disc brakes are very nice to have but hardly the only reason i installed it.
 
like i said the prop valve is not realy the issue it is the break master cylinder that gives you the spongy feeling. so i would install the axle hook up the breaks and go for a ride if it is too spongy for you liking look into the master cylinder upgrades that are covered many times here on the board. or just upgrade ot a 96 or newer brake booster/master.
 
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