Cradle drop questions

[kjpilot]

So, I want to drop my cradle .75"-1" to reduce some perceived stress from my 4" lift. I can't find a definitive "how-to" on doing this, but it looks pretty straight forward.

I'm planning on using three to four ~1.5" wide x .25" thick steel bars stacked up to the total height. I'm assuming the bottom face of the frame is flat from the front bolt to the rear bolt, so the bars can be solid (without cuts or bends) from front to back... is that correct? Is that how other people have done it?

I think I read somewhere that, as far as under the hood goes, all that needs to be done is loosen the hose clamps so the hoses don't crimp when the engine is lowered, are there any other concerns?

I do realize that the T-case needs to be lowered by the same amount, but I already know how to deal with that.

Any tips or bits of advice are welcome! Thanks!

 

[tjkj2002]

You will need longer cradle bolts to get proper thread engagement,the front 2 are M14x1.50's and the rear 2 are M12x1.50's.I can get you the exact lengths of the stock bolts tomorrow,they also are metric grade 10.9's and 10.9's must be used.Most places do not stock that long of metric 10.9 bolts so you will have to order them like I did since I needed shorter ones.Oh and they are not cheap,about $3-$5 each bolt.


If you have HD cooling(the mechanical fan) you may need to cut the bottom of the fan shroud so the fan does not hit the shroud also,which 100% defeats the whole purpose of HD cooling.

 

[kjpilot]

Oh yeah, the longer bolts! Good thing there's a Fastenal near my house.
I'd appreciate the length info, thanks!

Is the bottom surface of the frame where it contacts the cradle flat?

 

[tjkj2002]

Oh yeah, the longer bolts! Good thing there's a Fastenal near my house.
I'd appreciate the length info, thanks!

Is the bottom surface of the frame where it contacts the cradle flat?

Yep Fastenal is were I got my bolts from.The surface is flat but not 100% straight,there is a bow inward(towards the engine on both sides) right where the strut assemblies are.

 

[J-Thompson]

If you have HD cooling(the mechanical fan) you may need to cut the bottom of the fan shroud so the fan does not hit the shroud also,which 100% defeats the whole purpose of HD cooling.

Yes do not cut the shroud
I cut mine on my TJ when I installed the Tummy Tuck and had some high temp issues
better thing to do is to remove the shroud and cut new holes in the plastic for the mounting bolts
I used a Dremel to cut slots then used fender washers and adjusted as needed

How shore are you that you will need to lower the T-case?
I ask because guys with TJ's do 1" Motor mount lifts all day long to help with drive line vibes and to avoid a T-case drop
would dropping the motor only 1" be the same as rising it?
or could you some way fab up a 1" MM lift for the KJ
you coul then do the Cradle drop with out the T-case drop for sure

skip that part about the T-case drop
Just thought you are raising the rear when you drop the front
and dropping the rear when you raise the front ,the front being the motor and the rear being the T-case
but the 1" MM lift would make the need for a T-case drop null

 

[tjkj2002]

Yes do not cut the shroud
I cut mine on my TJ when I installed the Tummy Tuck and had some high temp issues
better thing to do is to remove the shroud and cut new holes in the plastic for the mounting bolts
I used a Dremel to cut slots then used fender washers and adjusted as needed

How shore are you that you will need to lower the T-case?
I ask because guys with TJ's do 1" Motor mount lifts all day long to help with drive line vibes and to avoid a T-case drop
would dropping the motor only 1" be the same as rising it?
or could you some way fab up a 1" MM lift for the KJ
you coul then do the Cradle drop with out the T-case drop for sure

skip that part about the T-case drop
Just thought you are raising the rear when you drop the front
and dropping the rear when you raise the front ,the front being the motor and the rear being the T-case
but the 1" MM lift would make the need for a T-case drop null

Unfortunately you can not use your idea for the fan shroud on a KJ since the HD cooling shroud also houses the electric fan so that would be off center also.

As for dropping the t-case the same amount is need when doing a cradle drop on a KJ since you are lowering the engine(which is held up by the cradle) so that would point the rear t-case output up creating really wack driveline angles which causes vibes.In a TJ doing a "motor mount lift" is doing the opposite by pointing the rear t-case output downward(but pointing the front output upward) without lifting the t-case/trans mount the same amount.

 

[J-Thompson]

Unfortunately you can not use your idea for the fan shroud on a KJ since the HD cooling shroud also houses the electric fan so that would be off center also.

As for dropping the t-case the same amount is need when doing a cradle drop on a KJ since you are lowering the engine(which is held up by the cradle) so that would point the rear t-case output up creating really wack driveline angles which causes vibes.In a TJ doing a "motor mount lift" is doing the opposite by pointing the rear t-case output downward(but pointing the front output upward) without lifting the t-case/trans mount the same amount.

yeah I realized that after I posted it
thus the correction at the end

but could you not fab a 1" MM lift so that when you do a 1" cradle drop you could off set the need for the T-case drop with the MM lift
the MM lift would also take care of the need to cut the fan shroud

so you do a 1" Cradle drop
this lowers the front diff thus making the angles on the CV's better
then do a 1" MM lift
this puts the engine back where it was thus every thing else is where it should be ,cooling lines and T-case
which then brings up the question
could a cradle be pulled from another KJ and modified with a 2" MM lift
a riser of sorts for the rack and pinion and then installed with a 2" spacer?
could then some fabed up longer clevis forks be made and thus a taller lift is born
the only draw back would be the knuckles

 

[tjkj2002]

yeah I realized that after I posted it
thus the correction at the end

but could you not fab a 1" MM lift so that when you do a 1" cradle drop you could off set the need for the T-case drop with the MM lift
the MM lift would also take care of the need to cut the fan shroud

so you do a 1" Cradle drop
this lowers the front diff thus making the angles on the CV's better
then do a 1" MM lift
this puts the engine back where it was thus every thing else is where it should be ,cooling lines and T-case
which then brings up the question
could a cradle be pulled from another KJ and modified with a 2" MM lift
a riser of sorts for the rack and pinion and then installed with a 2" spacer?
could then some fabed up longer clevis forks be made and thus a taller lift is born
the only draw back would be the knuckles

Below is the engine/rack&pinion/diff cradle from the KJ,I don't see anyway to do a 1" MML without welding.

You must be registered for see images attach

 

[TexasRock]

You will need longer cradle bolts to get proper thread engagement,the front 2 are M14x1.50's and the rear 2 are M12x1.50's.I can get you the exact lengths of the stock bolts tomorrow,they also are metric grade 10.9's and 10.9's must be used.Most places do not stock that long of metric 10.9 bolts so you will have to order them like I did since I needed shorter ones.Oh and they are not cheap,about $3-$5 each bolt.


If you have HD cooling(the mechanical fan) you may need to cut the bottom of the fan shroud so the fan does not hit the shroud also,which 100% defeats the whole purpose of HD cooling.

So you would need longer than the 1.50's then... since this is metric, what would it come to with the added 1" for the drop?

 

[TexasRock]

Ttt

 

[michalf]

Is lowering of the HD fan shroud straightforward enough (say, by 1")? I guess it is the most reasonable way to keep the viscous fan right in the center of the water pump.

 

[tjkj2002]

Is lowering of the HD fan shroud straightforward enough (say, by 1")? I guess it is the most reasonable way to keep the viscous fan right in the center of the water pump.

The mechanical fan is screwed on the WP,it will drop down when the cradle is dropped.The fan shroud is bolted to the radiator which can not be dropped down,you have to take the mechanical fan off or cut the whole bottom out to clear the mechanical fan.

 

[BjBnet]

wow, this is interesting stuff. First time I hear of the cradle dropping thing. I love this site....

 

[tommudd]

Funny how this subject comes up about every 6 months, then dies away once again.

 

[michalf]

I guess this is a very rare mod. But if you are building upon IFS instead of SFA, this can combined with a decent lift give more wheel clearance without abusing CVs.

I will probably try this mod if there are no issues other than the fan. My CVs are nit really happy with my current lift :-/

 

[05kj6spd]

How about instead of dropping your cradle you look into upgrading your CV's. There is a company called RCV that makes custom CV axle that are crazy strong. I believe they could take care of the angle issues as well. They aren't cheap but may be worth it to not have to drop everything lower.

 

[michalf]

No, it would not be the same. Currently, despite the JBA UCA, my front wheels have only about 5cm drop left. Which ***** badly. If I drop the cradle, I would:

- have less stress on CV, and more straight angle when driving flat
- have more available wheel drop
- can still fit larger tires and keep the lift

I am looking to drop the cradle by 3/4", and at the same time flip the ball joint in UCA + add a thin spacer.

If I do it, I will try to post a few photos too.

 

[tommudd]

Good luck
you make it sound simple, lots more to it
and flipping the ball joint with a thin spacer not a good idea, going to be a lot of stress on it

 

[michalf]

I am still exploring possibilities, nothing is decided yet.

I was thinking how to extend the UCA balljoint (JBA has this kind of a 2" extension) and was inspired by these guys: http://www.355nation.net/forum/how-chassis-suspension/27148-how-ball-joint-flip.html . I guess I could get 1/2" just by flipping the balljoint on JBA UCA (mount it at the bottom instead top) and adding a thin spacer.

Or I could find a good Dana 30 and do a SFA conversion. I guess more future-proof :-D

 

[Ry' N Jen]

I was thinking how to extend the UCA balljoint (JBA has this kind of a 2" extension) and was inspired by these guys: http://www.355nation.net/forum/how-chassis-suspension/27148-how-ball-joint-flip.html . I guess I could get 1/2" just by flipping the balljoint on JBA UCA (mount it at the bottom instead top) and adding a thin spacer.

Interesting idea.
But what works on a Chevy Colorado/GMC Canyon might not work
on a Jeep Liberty.
But hey, if you are willing to be the Guinea pig with you KJ, by all
means go for it!