Suspension Underslinging a Straight Axle

Drover

Well-Known Member
Nov 7, 2013
12,723
19,450
113
QLD
This is a rehash of a thread I've lost.......... detail how to undersling your Single Straight Axle.......It doesn't apply to drop/off set axles.

At All Times Remember You Are Under a Vehicle Supported By Stands Think Safety Always.



Now I would advise a flat concrete area to work on, you will need 4 x large jack stands, not those caravan stacka jacks either, you need a good bit of height under it......big shifter, pliers, new U bolts with NyLock nuts and HT washers, 2 x 10mm axle spacers....empty water tanks, remove spare.

Be very mindfull of slip when getting your van on and off the stands, do not use the jockey wheel, it will move and is unstable.

Do Not Use a Scissor
Jack for anything it will kill. A bottle jack or trolley jack to lift is the safest way.


Now before I started I scribed a line down the spring from where the axle sat on top of the spring to the bottom of the spring on both springs, I then measured from this lower point to a spot on the chassis which I marked, I did this on both sides so I could align things when job completed, it's hard to describe and sorry if it sounds a bit iffy....... basically just trying to square things...................

Jack up van with wheels approx 100mm off the ground if possible, gives you plenty of room and makes it easier when you put it back together, put jack stands under rear of chassis then lift the front up and put stands under the chassis at the front, I had my stands about halfway between end of vehicle and spring hangers and a third of the way back from the front.
Do Not Support or lift from jockey wheel or draw bar, you can actually bend things, the Draw Bar lifts with a pivot method, a dry lift to raise wheels will overload and bend it you must use the chassis. rails.

DO NOT USE THE JOCKEY WHEEL AS A JACK or a stand, in fact remove it before starting, remove wheels, scribe the position of the spring position on axle and mark axle as top and left or right side, disconnect handbrake cable from drum, brake power cable on axle, undo the U bolts, pop a shackle pin and roll out axle.
On the bottom of the axle you will see a 10mm spacer block which the spring sat upon, this holds the position of axle and gives room for the centre bolt, this needs to be on the opposite side of the axle now so measure and transcribe the position to the top of your axle, the block is usually spot welded in place but no need to remove it just put a new one in the new position, accuracy means you will keep the same profile, you cannot just rotate your axle , your brakes wont work and alighnment will be out, Don't Do It.

At All Times Remember You Are Under a Vehicle Supported By Stands, always have someone to help and keep the work site tidy.

Rebolt your spring and push your axle into position under the springs, jack it into position and using NEW U bolts preferable with HT washers and Ny Lock nuts, bolt it up and connect up all the other bits. You will need to check your U bolts nuts after a few hundred K's, do not reuse old U bolts as they stretch.
Keep an eye on tyre wear if it's just scrubbing slightly, measure from axle to a common spot on either side of chassis, say 350mm from front hanger and loosen U bolts slightly and just tap axle till the measurement is the same on both sides.



1516854381799-png.59213


These stands are good, wide top to hold and limit slide, HD.......................
1517260674457.png






These I wouldn't use as very little support on top,
1517260417998.png
are okay for supporting of axle but not wide sections when movement may occur,.
1516854511137-png.59214






NO< NO<NO<NO<NO ..........
1517260763340.png
.NO , NEVER......great for stab legs but not for support of vehicle on their own...DO NOT USE
1516854627051-png.59215




Now this is given as a guide only if you are unsure then don't try it, have help at hand, don't do it alone or use dodgy gear, while a simple task you could kill yourself or damage your vehicle...the onus is on you..............Keep Safe.
 
Last edited:

Chriso100

Member
Apr 26, 2020
33
38
18
Rosebud Victoria
Just lifted mine tonight. What an improvement! Fitted some 15" wheels and tyres also. The white ones are getting replaced with black steel and I might go some BFGoodrich all terrains too.
 

Attachments

  • IMG_0344.JPG
    IMG_0344.JPG
    265.3 KB · Views: 303

Chriso100

Member
Apr 26, 2020
33
38
18
Rosebud Victoria
Just a question after doing this modification on our van. I have heard a couple of negatives due to safety. I do understand the whole "axle on the bottom and it could fall out" safety aspect, but do I have anything to really worry about?? I used new U bolts and new nylock nuts. Could I please get some feedback from a few here?
 

Boots in Action

Well-Known Member
Mar 13, 2017
2,054
1,806
113
Ferny Grove, Queensland
Just a question after doing this modification on our van. I have heard a couple of negatives due to safety. I do understand the whole "axle on the bottom and it could fall out" safety aspect, but do I have anything to really worry about?? I used new U bolts and new nylock nuts. Could I please get some feedback from a few here?

Hi @Chriso100, I do not think you have any thing to worry about as it is done on many vans, mine included IMHO. As long as properly done, there is no increased chance of axle "falling out". My "U" bolts have double locking nuts which is more than they had before axle was changed. Jayco does this for customers before they take delivery if requested (my Daughter's new Journey was altered before she took delivery. ) @Drover's instructions are good and the main thing is to get axle on both sides of van at right angles to body and parallel. Mine was altered nearly 5 years ago and no problems - best thing I ever did - no bum drag on dips or gullies and no change to towing/tracking. Oopps! I lie! I had to alter the tow ball to a higher setting as van hitch was slightly higher- just reversed the tongue and van now perfectly level when connected to tug. There are lots of earlier posts on this. I will see if I can find them for you.
 
  • Like
Reactions: Chriso100

Drover

Well-Known Member
Nov 7, 2013
12,723
19,450
113
QLD
You have nothing to worry about as stated it gets done by dealers and the axle falling off is just a load of BS, if the axle lets go either way, on top or under you will be in trouble big time, so long as the axle is fitted in the same aspect as before and you fitted the spacer in exactly the same spot as it was on the bottom of the axle then your alighn should be near spot on and all will be good ............ To check position of axle. measure back from a central point on hitch to your chassis rail and mark on both sides, a spot you can get a straight measure from axle, then from the same position on both sides of axle measure to that point they all should be the same, you can do this to both front hangers to see if they are square them measure to axle , sometimes the hangars are out of align......
Hope that helps, I did many miles with my old 14 done this way, check the tension later as things do bed down. If you find wear on tyre just measure, loosen U bolt and give a tap with hammer till it measures up.
 
  • Like
Reactions: Chriso100

Dingo193

Active Member
Feb 17, 2017
144
120
43
On the road
Ill back Drover up . Got my songle axle done which had 90 deg bent axles. Turned them and got a juge amount of lift. Trailer manufacturer said no issues. We even had to turn them 45 deg back so it wasnt outragously high. Went well. Even had to bend towbar tongue the other way to match lift kit and van. No issues.
 

Drover

Well-Known Member
Nov 7, 2013
12,723
19,450
113
QLD
The hardest part is lifting it to the right height so when you pull the axle out you can just roll it under the spring....... Made that mistake the first time I did it, "missed by that much" took wheels off, wrestled axle into place, bolted it up then let tyres down before replacing them..............