Reversing the axles on a dual axle 19ft 6 inch Jayco Starcraft

Woodpecker · Veteran Member

Reversing the axles on a dual axle 19ft 6 inch Jayco Starcraft

Explorer · Guru

The biggest problem is the locator stud on the axle itself. The first leaf has a hole that sits around a stud inserted into the axle that stops the axle moving around. The way I did it was to reverse the axle left to right & then swap the brake backing plates so that they were the right way around. May be easier to take the axle to a spring works to be modified. Other than that there shouldn't be any problems. Probably haven't used the right terminology but You should get what I mean.

Mike.

erad · Guru

Be aware that most solid axles have some toe-in built in to them, The makers claim it is to give stability to the towed vehicle, but I think it is simply the way they make the axles. They weld one side and the weld shrinks as it cools. They then weld the other side and as it cools the new weld shrinks, but not as much as the first and voila - you have some misalignment. If you invert the axle, where you may have had toe-in, you will now have toe-out, and your tyres will wear. Trust me - I know about it...

I had massive toe-out with my 1999 build Jayco poptop. About 10 mm. Jayco didn't want to hear about it and referred it on to Al-Ko who built the axle. Al-Ko did try to fix it but short of cutting the axle off and starting again, no go. It is easy enough during assembly for Jayco people to run a tape measure over the front & back of the tread and check that it is toe-in not toe-out, but no. Then Jayco assembled the axle about 20 mm offset so that the left U-bolt was directly under the chassis rail. So much for quality control... I wore out 4 sets of tyres trying to fix the problem and when I finally contacted Al-Ko, they asked me to send the axle to them and they replaced it for free. I had to centre the axle and weld the locating plates myself. Even the new axle had 5 mm toe-in, but thusfar the tyres show no signs of wearing unevenly, so I think I have finally solved the problem. Now I will probably sell the van and get another... Incidentally, my previous van was even worse - it had 11 mm toe-in from new, so I am heading in the right direction. Another 5 or 6 vans and I may finally have a good one.

-- Edited by erad on Sunday 13th of March 2016 04:42:45 PM

Aus-Kiwi · Guru

I would keep them the same as not reversing them . Depends on leading trailing brake system too ? I would adapt axle to fit .

KJB · Guru

Keep it simple. Do no do unneccessary alterations. Probably only have to remove the centre bolt in the spring and put it back upsidedown . Axle may or maynot require a little bit of surgery for the centre bolt location bracket. (some are welded , some are not ,depends on the style used)

KB

KevKim37 · Senior Member

We had our previous dual solid axles bent to correct wheel alignment by a Specialist Wheel Aligned in Shepparton Vic. The technician who carries out Truck Wheel Alignments and heaps of Caravans as well advised me that even after manufacture. As most Solid axles though straight to start with, by the time the van is finished the axles require bending to correct alignment problems.

Cheers Kev.

Leather Tech · Veteran Member

On my previous van 18 foot Jayco pop top I did what you are planing to do, yes it did raise the van but the down side was I then needed to raise tow hitch to maintain a level van, when trucks overtake it sucked the van in which did not happen before, increased fuel consumption by 1.5 let per 100km. The fuel consumption may have been affected by other influences.
In short would I do it again NO.
Regards Peter.

KevKim37 · Senior Member

If going ahead with the axle swap use 5/8" U-Bolts if original are 1/2". The Enginneer advised this as of Extra forces on U-Bolts in the Underslung Axle position.

I recently in 10/2014 carried upgrade to 50mm Dual 2 tonne axles, 12" Brakes , Larger Bearings and 16" wheels. I fitted myself at a mates workshop in Innisfail as I am a Mechanic. We have since then travelled 13,000 kms with about 1,000 kms of Dirt Roads and re-tensioned U-bolts once without any further problems.

If you look at the Avatar photo you can see I run fully loaded and even though the van is raised another 5 inches my fuel economy has Not changed as I have 11 yr records of fuel usage. Also the van handles as good if not better at highway speed than it did on the 14 inch wheels and lower height.

I now travel dirt roads without a worry of the smaller wheels/bearings/tyre assemblies.

Cheers Kev.

Aus-Kiwi · Guru

Tmk less weight on U bolts axle under Spring ..

patrol03 · Senior Member

Toe in is only used on steer axles as you need toe out on turns.On a solid axle trailer toe-in should be zero but a small amount of positive camber should be set so when the trailer is loaded the axle or axles return to close to zero camber.

PeterD · Guru

erad wrote:
Be aware that most solid axles have some toe-in built in to them, The makers claim it is to give stability to the towed vehicle, but I think it is simply the way they make the axles.

There is no toe in on trailer axles. There is some camber in some of them. The subject has come up before and arguments arose so I emailed Al-Ko. Their reply was that they build the axles as the manufacturers order them. If they order axles with some camber then the do so. If the manufacturer does not want camber they build the axles with parallel wheels.

There is some conjecture as to whether some camber is inserted as when the vans weight comes on the wheels the axle bends and the wheels sit up straight. My van had no camber so I inverted the the axles, the wheels did not lean in when I had completed the operation.

PeterD · Guru

Explorer wrote:
The biggest problem is the locator stud on the axle itself. The first leaf has a hole that sits around a stud inserted into the axle that stops the axle moving around.

Which van does that apply to? All axles I have seen have a plate with a locating hole welded to them. The spring has a bolt through the middle with a round head in it.

If you wish to relocate the spring under the axle you have to grind the locating pad of the bottom of the axle and re-weld it to the top. You then remove the spring centre bolt and insert it in the opposite direction.

Aus-Kiwi · Guru

On a bean axle ? You would have to assume the axle is too light if they allowed for axle bending under load . To say nothing about bumps etc .

patrol03 · Senior Member

Sorry,not correct AK. On single axle vans usually there is a small amount of camber built in for the reason I quoted previously.Some years ago I had a problem with tyre wear on my single axle Millard.We had done a lot of work in the van and it was always heavily loaded as family vans usually are and on checking it in the loaded position with my camber gauge it gave a negative reading..hence the wearing of the inside of the tread.I removed the axle,took it to the local spring works (hard to find these days) where I specified a 5/8in bend at the centre in the press.Sounds a lot but over the total length of the 2.2m axle you could only just see it.Once refitted to the van with new centre bolts in the springs and u-bolts tightened,when lowered to the ground ,the 5/8 kick we inflicted, reduced to almost half that figure and when loaded, minimal registration of positive camber was recorded.The same van went on to do another ten years work carting the family and their gear around the country.No more abnormal tyre wear to the day I sold it. So yes,axles do bend under load.Next time you see a box trailer leaving the garden centre loaded with a cubic metre of sand pay particular attention to the camber of the wheels,likewise following an older caravan along the highway. I guess 40 years in the motor trade alerts me to these things.

Aus-Kiwi · Guru

Yes more to do with side load on cornering . Much the same as vehicles ..