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Unread 02-17-2012, 07:20 PM   #1
jhumphrey
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Post-8.8 Swap Quirks: Diagnosis Needed

Ok, so my long awaited and highly anticipated 8.8 swap was finished today. It was not without its hiccups...a broken driverside rear leaf spring was discovered which led to me putting a 2" BDS lift on it.

Heres what was done while it was down:

d35 was removed, '01 Explorer 8.8 installed
2" BDS springs/bushings
4.56 Yukon gears (master install kits used)
Spartan locker in the d30
All new brake components for the 8.8

The good:
- The jeep has more "oomph" on take off and feels "more responsive"
- BDS springs are much smoother than my shot factory ones
- Ebrake works MUCH better

The bad (heres where I need help):
- There seems to be an issue with the brakes. They feel like they have air in them, but Im pretty certain they don't. They are soft and go pretty much all the way to the floor. The brakes have been bled several times, same results. If it's not air, then what else could it be? I know that I went to disc brakes in the rear, but I didn't read anywhere in swap threads that I would need to change out the Master Cylinder or Proportionate Valve. Did I miss something or is there a "larger" issue?

- There seems to be some sort of binding in the front, passenger side. It pops when I turn the wheel. Is this caused by the locker? It almost "grabs" the jeep throws it that way, then it pops. My transfer case is not engaged (its in 2H).

- There is a very noticeable whine when traveling down the road ; which I have dismissed as new gears that need to break in.

- My speedo is waaayyyy off. Once again, I expected this, but it was surprising as to how much. I was showing 55MPH @~2k in 4th gear, my friend was behind me and told me he paced me at 40MPH.

Im getting back with my mechanic about the various issues, but would like to have an idea of what we should look at. I picked up the jeep today before he had a chance to drive it (he's a buddy of mine), so it'll be going back to his shop for final tweaks. I just need a consensus on what we should be looking for.

Thanks all!

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Unread 02-17-2012, 07:48 PM   #2
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jhumphrey,
On the brakes, did you verify that the bleeders are on the top. You can get a new speedometer gear for quadratec http://www.quadratec.com/jeep_knowle...article-46.htm
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Unread 02-17-2012, 07:51 PM   #3
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Quote:
Originally Posted by ROWA View Post
jhumphrey,
On the brakes, did you verify that the bleeders are on the top. You can get a new speedometer gear for quadratec http://www.quadratec.com/jeep_knowle...article-46.htm
Yes, the bleeders are on top. When we bled them, they felt stiff, so he drove it around the block. It seemed ok to him, though he said it was a bit softer than he liked, but this was probably due to going from drum to discs. On my way home, after the vehicle had really "warmed up" (I was about 3 blocks from the shop), it was back to being super soft (basically all the way to the floor to stop). Previous to that it was soft, but not all the way down.

Could there still be air trapped in the line somewhere?

Im planning to go to 33" tires in the future. I may have to bite the bullet and get the correct speedo gear for 31"/4.56. I don't think I can handle a messed up speedo for THAT long . I also presume if Quadratec has a - that means you don't need to change the gear? It shows Ill need a 42 tooth gear for the 31"/4.56 combo. For a 33"/4.56 combo, it has a dash. The dash stays until you get to a 35"/4.56 combo, where you get a 37 tooth. Does that mean a 42 tooth is good for 31" and 33"?
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Unread 02-17-2012, 08:24 PM   #4
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jhumphrey,
I had to bleed my rear brakes several times, before I got all of the air out of the lines. Some times the proportioning valve needs to be replaced, I was lucky my brakes seem to work with the original valve.
With the 4.56 gear and the 33" tire a 39 tooth gear would be the correct one, according to the table. When you install it you need to check the housing on the transfer case, it specifies the orientation on how to re-install it.(Clocking). I got a gear for 33" tires and was running 31" at the time, the speed was about 3 miles slow, now with the 33" tires it is right on.
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Unread 02-17-2012, 09:54 PM   #5
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^ Exactly what ROWA said, it takes a few times bleeding to get it to stay firm. It took me an ungodly amount of time to bleed them (idk why) but they are now nice and firm as they should be
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Unread 02-17-2012, 11:07 PM   #6
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Everything seems pretty normal except for the popping. You might want to get that checked out. It could be the locker popping your tires forward a little even though they're turned. The master cylinder and brake booster swap are common after changing to disk brakes because they do seem to need a little extra oomph.
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Unread 02-18-2012, 05:17 AM   #7
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Quote:
Originally Posted by Anticanman View Post
Everything seems pretty normal except for the popping. You might want to get that checked out. It could be the locker popping your tires forward a little even though they're turned. The master cylinder and brake booster swap are common after changing to disk brakes because they do seem to need a little extra oomph.
I was hoping you'd chime in Anti. I was wondering if the spartan was hanging up or something. I hear that they are supposed to be "invisible" when the CAD isn't engaged, but then I read that sometimes the still pop and grab. Right now, it's pretty aggressive. Ill be getting an ARB/OX asap if that's the case. I can tell already that Im not going to be a fan of it.

Im going to get the jeep back to my buddy today and see if he can figure out the brake bleeding and get her to working there properly (of course). Maybe they just haven't been bled proper...I have my fingers crossed. After my BDS "upgrade", Im pretty tapped out to be spending more money for parts.

If I have to swap out MC's, do I replace it with a factory one or one from a different vehicle (to get more oomph)?
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Unread 02-18-2012, 09:29 AM   #8
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Get a master cylinder from a 95 wrangler. A lot more flow to the brakes and it might fix your soft pedal problem.

And yes, it has been reported on some new front lockers that the tire will hang up and make a chirping sound at first. You just need to put some miles on it and it should stop.
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Unread 02-18-2012, 09:49 AM   #9
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Quote:
Originally Posted by Anticanman

This is a very viable answer. Jhumphrey, do you have a front locker though? When I had my Detroit in the Dana 35 it would push me straight through the corners and depending on the type of rubber you're running you can get everything from a lunging to a chirping to no front traction at all. It was quite scary for me to drive with it back there because I sometimes think its a Ferrari on my way to work in the mornings. I ended up with the truetrac out of sheer luck and it's a thousand times better in the corners and not too shabby offroad (just not on rocks)
I do have a front locker. Sorry, I should've been clearer on that. The Spartan is in the front (Dana 30). That's why I am surprised when it "grabs". I thought I wouldn't notice it with it in 2wd, as the axle is disengaged. Am I wrong about that??

As far as putting a 95 MC on, is that a direct bolt on (mines an 89 4.2L)?
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Unread 02-18-2012, 09:49 AM   #10
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Quote:
Originally Posted by Dreygo View Post
Get a master cylinder from a 95 wrangler. A lot more flow to the brakes and it might fix your soft pedal problem.

And yes, it has been reported on some new front lockers that the tire will hang up and make a chirping sound at first. You just need to put some miles on it and it should stop.
This is your answer. I've even got a little chirping in LS mode in my locker up front.
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Unread 02-18-2012, 09:52 AM   #11
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Quote:
Originally Posted by jhumphrey View Post
I do have a front locker. Sorry, I should've been clearer on that. The Spartan is in the front (Dana 30). That's why I am surprised when it "grabs". I thought I wouldn't notice it with it in 2wd, as the axle is disengaged. Am I wrong about that??

As far as putting a 95 MC on, is that a direct bolt on (mines an 89 4.2L)?
Just give it time and see how it plays out. And yes, the MC should be a direct bolt on or you can go bigger and cheaper with one from a ford e-350 van. The little tits need to be ground down for a flat mount on that one. Part number M2008 at napa IIRC

You were clear on that, I misread it and hoped no one had quoted me before I deleted it. But you're quick!
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Unread 02-18-2012, 10:01 AM   #12
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Quote:
Originally Posted by ROWA View Post
jhumphrey,
I had to bleed my rear brakes several times, before I got all of the air out of the lines. Some times the proportioning valve needs to be replaced, I was lucky my brakes seem to work with the original valve.
With the 4.56 gear and the 33" tire a 39 tooth gear would be the correct one, according to the table. When you install it you need to check the housing on the transfer case, it specifies the orientation on how to re-install it.(Clocking). I got a gear for 33" tires and was running 31" at the time, the speed was about 3 miles slow, now with the 33" tires it is right on.
You are looking at the chart for the electronic driven speedos for 93-06 years. He has a '89 YJ so he has to use the chart at the bottom.
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Unread 02-18-2012, 10:07 AM   #13
jhumphrey
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Quote:
Originally Posted by Anticanman

Just give it time and see how it plays out. And yes, the MC should be a direct bolt on or you can go bigger and cheaper with one from a ford e-350 van. The little tits need to be ground down for a flat mount on that one. Part number M2008 at napa IIRC

You were clear on that, I misread it and hoped no one had quoted me before I deleted it. But you're quick!
Luck of the draw on replying quick

I saw a write up where they used the E350 mc. It said they had an adapter from autozone, but they didn't supply a part number. Maybe my autozone will know what adapter that is...

As far as the brakes themselves, I may try to bleed all 4 myself tomorrow after work and see what results I get. I wasn't particularly fond of his bleed method, so air could be simply trapped.

Now, the locker. I dont remember reading that a wheel can lock up on you. Seems dangerous. I plan to go selectable in the future, but that's $1k I don't have as of the moment for one. So, hopefully the locker just needs a little break in time.

Looks like I'll order a new speedo tooth to 15mph off is to much for my taste. A $40 tooth is cheaper than a $200 ticket

What a project this has turned out to be
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Unread 02-18-2012, 10:07 AM   #14
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I too think E-350 is cheapest and easiest fix. Plenty of threads to learn from.

Read every chart you can on speedos, and shop around. Between Morris, Ebay and Quad, you find good deals.
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Unread 02-18-2012, 10:09 AM   #15
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Quote:
Originally Posted by Sprungover

You are looking at the chart for the electronic driven speedos for 93-06 years. He has a '89 YJ so he has to use the chart at the bottom.
^ this.

I guess there is no difference in tooth sizes from 31"-34", judging by quadratecs chart. That sort of works in my favor, I'll save $40 when I go 33" if I go on and order it for the 31" (current) tires.
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