new 31" s got that bump steering thang goin on-ideas?

[3jeepsdeep]

Sorry for long post :roll:

I just HAD to have 31" tires. and now my 77 CJ7 is SO hard to drive straight down the road.

Here's what I got:
77CJ7, 304 3speed, manual steering, new 31" tires (fairly open tread, not too aggressive), stock suspension / shackles, etc., 41k miles (yeah - that IS original), gas shocks 28 kmiles ago

Here's what I did:
new ball joints (rt side was worn/ broken), snugged-up steering gear lash, wheel bearings are snug, added a heavy duty steering damper, checked tie rod ends, had front end alignment done.

The 'bump' steering is somewhat better after adding the stabilizer - but here is something very curious and very annoying that I can't figure out...

In 2wd with front hubs disengaged, when I accelerate, the jeep will drift to the left, when I take my foot off of the gas, it will drift back right. This might have been happenin before the 31"s, but if so it wasn't noticeable.

Buddy of mine said he had installed a reverse shackle kit to address same problem and it worked. This is a head scratcher for me, anyone game to noodle on this or know if the reverse shackles help?


I drive it daily - and it DOES keep me awake trying to go straight.....or maybe it's the hedders that keep my eyelids open.......
thx
df :razz:

[pyagid]

when was the last time the alignment was checked? If you tightened up all the steering components, the alignment could be out of spec now. Also with the acceleration thing, Make sure your motor mounts, and tranny mount are in good condition. I have seen that symptom when the entire drivetrain is moving due to broken mounts.

My experience, the shackle reversal makes a much nicer ride on road, only problem is under hard braking it will nose dive. But i dont think this will be a solution to your problem

-Paul

[Mudrat]

Ditto the alignment - new ball joints will change geometry. Also check your tire air pressure. Had the left-drift problem in the wife's Chebby and turned out the air was 10lbs low on the rear drivers side.

Might also check the spring bushings - I had a similar issue with my 75 CJ5 and found the rubber was worn bad letting the springs wander.

Mudrat

[3jeepsdeep]

thanks for replies -- alignment was done recently after ball joints & everything else. I didn't think to check spring bushings, guess that's next. Air pressure in tires is good all 'round - higher pressure than old tires, tho -- these 31's run at 44 psi.......

will double chek engine / trans mounts, but all are relatively recent.
thx

df
:t:

[Lifted79CJ7]

Also check your steering box for slop - or maybe the u joints in the steering shaft. Those larger tires could have been just enough to show these problems. I developed a lot of similar problems after stepping up to 33"s in my 304 powered CJ7.
Just a thought,
Jack

[Goose]

I dont want to belabor the obvious here, but the drift left under accell and right under decell is "normal" it is the torque and the fact that you are actually lifting the left front a bit under accelleration and compressing it under decell..so if the steering box is mounted to the frame and the steering gear to the axle (as it is) when you move the two in opposite directions like that it actually "turns" the wheels as to why it only showed up after the 31" s added I don't know ..

[tufcj]

I had a Toyota that did the drift thing, it turned out to be that the centering pin in one of the rear leaf springs had sheared, and the u-bolts weren't tight enough to hold the axle still. The rear axle would shift front/back about 1", enough to cause a considerable "drifting" feel.

It could also be bad spider gears in the rear axle, but that would make noise when turning too.

Just another thing to check.

Bob
tufcj

[thejeepingoat]

i would lower the pressure some, 44 psi seems awfull high for such a light vehicle.

[Goose]

Holy cow yea.. Drop that tire pressure.. 44 psi is a bunch I run my CJ-5 at 30 psi.. the recommended pressure on the sidewall is for the maximum load rating of the tires (i.e. to get the load rating you must inflate to max pressure )

[rollen dean montoya]

you should never run the tires at max pressure. unless you are towing
or have loaded up like a pack animal you should run at 38 to 40 psi
in those tires.on the eagle i run my tires at 32 psi. the max pressure is 35
psi. the my dad has a 2004 grand cherokee with pirelli scorpions
235/75-15's the max pressure is 44psi and he runs 40psi cold 30psi for
snow,mud,and ice. as far as the steering problems, go back thru the list of work you had done and check everything. you may have missed something.
good luck, rollen :lo1l:

[3jeepsdeep]

hey y'all - thanks much! I appreciate the recommendations. I will try knockin the tire pressure down (I double checked - tires are at 38 right now, rated for 50. ) I thought about the torque effect on the steering box but thought that SURELY some bright Toledo / Detroit design engineer had long ago figured out how to design that out .. oh yeah - this IS a Jeep...

Spring center bolts seem ok all 'round.

thanks again -- will let you know how the experiment progresses.
df :sa:

12/7 -- morning update - set tire pressure to 30 on all 4 -- noticable improvement in handling on my 27 mi. commute. Now I can go back to dozing at the wheel. Lesson here, I guess, is not to assume that the tire pressure set by the tire installer is the RIGHT seting.
df

[mrtazwrench]

most of the time i set it at the spec recommended for the vehicle. :t:

[Goose]

Yep Tire pressure either to much or too little can do wierd things.
On my Semi You could feel when one of 8 dirve tires were low.. it would get vague and wander under accel or decel..you would think the other 7 would mask it but it was there..

[Mudrat]

12/7 -- morning update - set tire pressure to 30 on all 4 -- noticable improvement in handling on my 27 mi. commute. Now I can go back to dozing at the wheel. Lesson here, I guess, is not to assume that the tire pressure set by the tire installer is the RIGHT seting.
df

Glad to hear things have improved
To review a bit, the pressure listed on the sidewall is the max pressure needed for the load rating. There have been several articles in numerous 4X4 mags on how to set the correct air pressure for your particular ride. Basically air up & draw a fat white chalk line across EACH tire and drive a straight line for 25-30 yards and look at the "wear pattern" on the chalk. Drop pressure and repeat until the chalk line on EACH tire is warn across the tread. That will be your 'ideal' pressure at that weight.
What this does is account for the weight differences front/rear and left/right. It will change with load. For example in the truck, when the bed is empty I'm about 35 lbs F/R, but when I haul 1500 lbs of gravel or rock, or put the Jeep and trailer on, I'm up to 45 front and 55-60 LBS rear(this is a Dodge HD2500, long bed, 4dr by the way). I haven't tested my CJ yet with the 35's since it's not on the road - - - yet.

Mudrat

[rollen dean montoya]

glad you got the problem solved =D> :mrgreen:

[cheapjeep]

I have to keep one of my back tire's at 27psi and the other at 28psi. If I don't the locker will throw me all over the road when I speed up or slow down :shock:

[rollen dean montoya]

that can't be good :shock: #-o

[3jeepsdeep]

Thanks for the help, y'all!! the 'wandering Indiana' tire problem is mostly resolved, no worse than any of the other typical stuff.

here's a few pic's from way before the great tire upgrade (hey, it's what I have, ok?).

http://www.fullsizejeeps.com/jeeps/getimg.php?image=1974-1983-Cherokees/77 FSJ wannabe.JPG

http://www.fullsizejeeps.com/jeeps/getimg.php?image=1974-1983-Cherokees/77 FSJ wannabe under hood.JPG

And way earlier yet before big project (was delivered to me in boxes in 1998 -- "Christmas Present for wife:' Hey, she got to do first fire / start; present enuff, right?? I'm sticking with jewelry ever since).

http://www.fullsizejeeps.com/jeeps/getimg.php?image=1974-1983-Cherokees/77 FSJ wannabe B4 project front.jpg

http://www.fullsizejeeps.com/jeeps/getimg.php?image=1974-1983-Cherokees/77 FSJ wannabe B4 Project back.jpg

cheers df

[Mudrat]

Looks like FSJ.com doesn't allow remote linking :-| Any other place you have them posted?

Mudrat

[3jeepsdeep]

Looks like FSJ.com doesn't allow remote linking :-| Any other place you have them posted?

Mudrat

Unfortunately no, sorry! Any ideas for free pic hosting or other ways to post a pic here?

I tried copy/pasting the link from my posting into a rowser address bar and it seemed to work even tho the pic wasn't originally displayed.

thx
df

[Mudrat]

Unfortunately no, sorry! Any ideas for free pic hosting or other ways to post a pic here?
df
There are a few out there that allow free hosting http://www.webshots.com/homepage.html and http://www.photobucket.com/ are the 2 most popular - photobucket may even be easier to use - not sure though. ImageStation no longer supports remote linking (for free) so stay away from there.

Mudrat

[3jeepsdeep]

thanks for the info on Webshot.

a couple 77CJ7 pics from reincarnation project in 1997-1998 - photo quality is poor on these 2


http://image20.webshots.com/20/5/37/93/230953793oTyPIg_ph.jpg

http://image30.webshots.com/30/7/18/98/230971898hcGgsI_ph.jpg

http://image30.webshots.com/30/7/19/26/230971926ikcWaS_ph.jpg

more recent shots (before 31's).



http://image30.webshots.com/30/5/39/8/230953908tKRCAs_ph.jpg


http://image20.webshots.com/21/5/40/18/230954018LfDqEx_ph.jpg

http://image22.webshots.com/23/5/40/74/230954074UrnZsP_ph.jpg

if these links don't work - my apologies.

regards
df

[Mudrat]

MAN!!! You did an awsom job of restoration!!! :t: :t: I was a bit worried with the gas can on the front bumper though :shock:

Mudrat =D>

[Lifted79CJ7]

So how do you like that DUI ignition system? That Jeep looks great!! =D>
Jack

[3jeepsdeep]

Mudrat -- LOL!!-- the 5 gal gas can strapped to the front got me back / forth from the pole barn to the heated garage for 15 months (first task - get it runin!!). only had to 'fillup 1 time in 15 months (only clocked 1 1/2 miles tho). I confess - I did drive it 'round the property for fun a few times - like a go-kart.

Jack - The DUI is awesome! I advanced the base ignition from 6 BTC to 9 BTC without any ping, and got a noticeable boost in pep. Also got rid of lots of wiring & stock ign. clutter. Hedders are fun, more pep, too - but cut economy from 16+ mpg to 14+ mpg on mix of hiway / town drivin. If I had to do over again, would look at injection - if anyone makes one for it.

I have uglier pics of the "pre-restoration" era and what was attempted by the previous owner - kinda scary. Also want to say that when I got this '77 'turd-in-the-rough' back in 1997 -- it had only 12256 miles on it -- confirmed original. 42k miles now, still like new (yeah, right!). Bought it from the guy who totaled it back in 1978 - he & his son started restoration but gave up at some point (was delivered to me as a carcase on a flatbed trlr. with 13 boxes of parts). I made LOTS of misc body brackets out of a refrigerator casing - Tappan , the world's leader in Kitchen appliances since 1882.

http://image20.webshots.com/21/1/38/70/232013870KicLPj_ph.jpg

and just what were they thinkin with this ??? Looks real Da** weak / dangerous! (I did new wheel house, panel, floorboard, and corner panel.)

http://image34.webshots.com/35/1/38/87/232013887rivHbE_ph.jpg

thanks for the comments! would like to see pics of y'all's rigs!! :mrgreen:
regards
df.

[Mudrat]

That's a pretty ewww-ga-lay 3Deep :? We have a Members Ride forum at http://www.bulltear.com/forum/viewforum.php?f=32 with pics from a lot of us, XRACER even has some video he posted a couple days ago.

Mudrat
No go VOTE!!! :t: