I did it

[NewcomerComanche]

I bought a comanche. 1988. The thing is god damn beautiful (besides the rust but New England is New England so)

 

I do have a few questions though. 

 

I've looked through the forums and seen many a post about brakes and am curious. My foot goes to the floor and it just starts to get pressure. Guy said it was the line, I haven't had time to run it anywhere to get it looked at. 

 

Also, and the most confusing thing of all, there is a pipe coming from what I see to be the engine block that has no cap, no hose, no line. It's off the driver side towards the front of the block and it extends past the header and curves upward?

 

Also notable that while running, there is some positive pressure  coming from the pipe but it's a rapid pulse, not constant like a fan. 

 

Will update with pics if people are still active on this forum

[jdog]

Welcome, congrats on finding a Comanche.

Pictures are worth a thousand words

As for the brakes, that could be a few things, if you pump on them does it raise the pedal at all? Has anything been replaced? I'm betting you have air in the system and it wasn't properly bleed.

[derf]

Welcome to the forum.  This place is pretty active considering how few MJs were built and how long ago.

 

Brakes are pretty straightforward to fix.

 

First start by a good bleed of the whole system.  Start with the back passenger side, then back driver side, then front passenger, finally front driver side.  Make sure the fluid level in the reservoirs doesn't get low or you get to bleed the whole system over again.

 

If you still have issues, my next step would be to replace old rubber lines.  One in the back, two in the front.  Naturally, you'll have to bleed the brakes again after installing them.  If you're doing this, it wouldn't hurt to swap in fresh calipers in the front and wheel cylinders in the back "as long as you're in there".  Parts are cheap and plentiful at Rock Auto.

 

If that doesn't fix it, you probably want to replace or rebuild the master cylinder.  And, of course, do round 3 of bleeding the whole system.  Another "as long as you're in there" proposition is to replace/upgrade the vacuum booster.  I don't remember the year they changed over but a newer XJ dual diaphragm booster bolts right in and works better than what the Comanche came with.  Again, Rock Auto has a good selection of parts available.  If you're going to replace the booster, one for a 2000 or 2001 Cherokee with a matching master cylinder would be the right choice.

 

 

As far as the hose, I'd need a few pictures to help.

[MiNi Beast]

Flintstone it. 😆 welcome 

[NewcomerComanche]

You guys are awesome, I didn't expect anything until this afternoon the earliest. 

 

Brakes are squishy running and off, returns to normal resting positions after pumping them.

 

Also I'm aware I'm missing an air hose from the intake box to the valve cover. The grommet is still there but the PO plugged the holes with tape and what looks like a finger from a cloth glove 🤦 anybody by chance have a part number on it?

 

First pic shows location (hard to see) but look just under the belt and you'll see the bloody gaping maw

[jdog]

This is just a heat riser

[Ollie]

Welcome to  the world of classic vehicles.....!!!!!!!!  sometimes..................but mostly 

 

Enjoy your new truck !!

 

Having Comanche Fun,

Ollie

[NewcomerComanche]

Just now, jdog said:

This is just a heat riser

So in other words, there's nothing wrong with the open hole? Or is there some cap or something to toss on it?

[jdog]

The two circled should be connected together @eaglescout526 can you assist with a part number?

Edited September 11, 2020 by jdog
Forgot to add pictures

[jdog]

Just now, NewcomerComanche said:

So in other words, there's nothing wrong with the open hole? Or is there some cap or something to toss on it?

Correct, there is a hose that goes between that and the airbox used for colder climates to heat the air in the airbox

[eaglescout526]

Hey that's weird it didn't @ me for some reason.

 

Welcome to owning that glorious Renix 2.5L.

 

PN for that hose is 53002877. But its no longer available. Honestly its just a hose similar to what all the old carbed stuff would use.

[jdog]

I forgot to click on your name

[eaglescout526]

Lol there it goes.

[Pete M]

there is a special brake bleeding procedure for MJs.  has to do with the emergency line running to the back height sensing prop valve.  the steps are in the link in my signature.  

 

if your truck is rusty and still sporting the original steel lines, now's the time to replace them all, especially the 2 lines that run along the gas tank where rot is most common.

 

also in that link are Cruiser's MJ tips.  do all that apply. 

[eaglescout526]

Be sure to register the truck. Looks like you have an auto 2.5L. Rare bird. Wonder if its got the A999 or the AW4

[JustEmptyEveryPocket]

17 minutes ago, Pete M said:

there is a special brake bleeding procedure for MJs.  has to do with the emergency line running to the back height sensing prop valve.  the steps are in the link in my signature.

Here is a thread that does a good job explaining the procedure AND the reasons for it. 

 

Welcome to the addiction! My advice is to check out all the Tech threads you can. Read, read, read some more. Best way to learn. Good luck!

[Pete M]

1 hour ago, JustEmptyEveryPocket said:

Here is a thread that does a good job explaining the procedure AND the reasons for it. 

 

Welcome to the addiction! My advice is to check out all the Tech threads you can. Read, read, read some more. Best way to learn. Good luck!

 

 

I like that thread better!  DIY is updated to reflect new thread.   

[Wounded_Fighter]

8 hours ago, NewcomerComanche said:

So in other words, there's nothing wrong with the open hole? Or is there some cap or something to toss on it?

Technically there use to be a hose leading this to a flap in the front of the airbox to heat the engine faster with exhaust heat not fumes.

 

But no its fine as it is.

[Eagle]

12 hours ago, Pete M said:

there is a special brake bleeding procedure for MJs.  has to do with the emergency line running to the back height sensing prop valve.  the steps are in the link in my signature.  

 

if your truck is rusty and still sporting the original steel lines, now's the time to replace them all, especially the 2 lines that run along the gas tank where rot is most common.

 

also in that link are Cruiser's MJ tips.  do all that apply. 

 

If you are in New England, definitely follow Pete's advice. It sounds like a daunting task but, in reality, once you dive in and get started, replacing all the brake lines isn't all that much work, and it's definitely worth the effort in terms of the peace of mind you'll gain.

 

I'm in New England, so I speak from experience. I've tried patching the steel brake lines. What a joke. On my '88 Cherokee -- a number of years ago -- I replaced the rear line from about the driver's seat back to the rear axle. Got it all buttoned up, my buddy came over to help me bleed it -- and it popped the same line, a foot forward from where I had spliced it, while we were bleeding it.

 

Don't get steel. New England states now have a love affair with the liquid auto eater salt compound, and that stuff is death to brake lines. Get cunifer (copper/nickel/steel). You can get a 25-foot coil from Amazon, with new fittings, for a decent price. And the cunifer is much easier to work with than the steel lines you get at the parts houses.

 

https://www.amazon.com/s?k=Cunifer+brake+line&ref=nb_sb_noss_2

[NewcomerComanche]

Alright you guys are seriously awesome

Now, I've bled brake lines before, but never so much as took a wrench to them. And I'm a man with limited wrenching experience. 

 

Can I do the brakes myself or with a friend's extra hand? How daunting of a task we speaking?

 

I already feel the truck calling for me to play with it though, I just wish I didn't work all god damn day

[MiNi Beast]

Brake lines are easy enough with some mechanical amplitude. Buddy could always help. You can do it. 

[Pete M]

the first time I redid brake lines I used the pre-made straight pieces from the auto parts stores.  I used a little bending tool and it was pretty simple.  the second time I bought a whole roll and a bag of ends and a flaring tool.  it was more complicated for sure (and I highly suggest practicing your flares before you start on the truck), but I did it and if I did another I'd go with a roll.  

 

a quality flaring tool makes all the difference.   

 

also, you shouldn't feel like you need to perfectly replicate the factory bends and routing, but do make sure nothing is going to catch or pinch the lines. 

 

also, also, now's the time to contemplate the dual booster swap with a normal prop valve up front and to delete the rear height sensing valve.  more info on those in the link in my signature.  

[87MJTIM]

15 minutes ago, Pete M said:

the first time I redid brake lines I used the pre-made straight pieces from the auto parts stores.  I used a little bending tool and it was pretty simple.  the second time I bought a whole roll and a bag of ends and a flaring tool.  it was more complicated for sure (and I highly suggest practicing your flares before you start on the truck), but I did it and if I did another I'd go with a roll.  

 

a quality flaring tool makes all the difference.   

 

also, you shouldn't feel like you need to perfectly replicate the factory bends and routing, but do make sure nothing is going to catch or pinch the lines. 

 

also, also, now's the time to contemplate the dual booster swap with a normal prop valve up front and to delete the rear height sensing valve.  more info on those in the link in my signature.  

 

 

Pete, so are you recommending swapping to an XJ prop valve?  

 

I have had the dual booster upgrade on my "to do" for several years.  The load sensing valve was deleted many years ago.  Planning on redoing at least all the rear lines when I do this.  Also, looking at disks in the back. Teraflex has a kit for D44 axles - $$$.  I was wondering about the distro block vs. the prop valve.

[Pete M]

yes.  you can also go with an aftermarket inline prop valve for the rear so you can dial it in juuuuust right.  

 

also, also, also, now is the time to contemplate a rear disk brakes swap.    super easy using ZJ parts

 

just imagine how awesome things will be will a whole new updated brake system

[NewcomerComanche]

Realistically speaking, I may stick with the stock brake setup, save for deleting the rear load valve. 

 

If the boosted brakes serve only to upgrade the brake capacity, then it's potentially something I'll look into later on. But right now I'm going to stick with the things to get it to pass inspection. 

 

Brakes, tires, hoses, and lines. Luckily, it seems there is minimal electrical work that needs to be done for the moment. I'm sure plugging into a computer will say otherwise but