Welcome to Manins' truck camper project

Suspension

Specifications for the rear spring pack from iveco:
* First stage springs move 10.2mm per 100kgs of weight,
* Second stage moves 2.7mm per 100kgs of weight.

Squeaky Leaf Springs

The rear spring pack is made up of two stages of parabolic springs. These are springs that reduce in thickness in proportion to the square of the distance from the centre. The first stage of three springs move 10.2 mm per 100 kg of load; the second stage single spring moves 2.7 mm per 100kg of load. The second stage spring has keeper brackets at each end, but these really do not keep the springs in alignment and if the spring moves (due to inadequate torque on the main U-bolts holding the axle and spring pack together), the first stage springs rub agains the brackets and squeak badly.

The ultimate solution for the squeaking is to realign the spring pack, but this is not easy and requires a lot of force. Easier is to put something between the springs and the keeper bracket. At first I tried Tuck's solution of inserting cut up kitchen board there. This worked very well for about 10,000 km but eventually the board broke up.

A different solution is now in place. Short lengths of 30 mm OD irrigation tubing have been shaped with the aid of a hot air gun to fit over the keeper brackets. They are held in place by M8 threaded rod and nuts. Hopefully, with less movement possible, these will last longer.

A pair of shaped tubes designed to stop squeaking of rear spring pack.

Passenger-side rear U-bracket with tubes installed. M8 threaded rod stops movement.

Driver's-side rear U-bracket given the treatment. Nylock nuts are used.


Update Nov16: After 20,000 km of mostly off-bitumen roads, tracks and overland travel through inland Australia, the tubing required replacing with new tubing. The spring pack on the passenger side was so much out of alignment that at first the tubing could not be fitted. The main U-bolts had to be eased off, and with a heavy ratchet strap in place to provide tension, the second stage spring was encouraged to move into position using a sledge hammer

Bump Stops

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Available from EVA or TravelTrucks, replacing the firm front suspension bumpstops with progressive load carrying bumpstops from Airbag Man improves stability and bump absorption. The kit, model LU8030, is simple to install using Loctite 262 threadlocker.

A 10 mm Allen Key is all it takes to remove the OEM bumpstops. The replacement threaded studs, coated with the Loctite supplied, screw in by hand.

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Progressive bumpstop on driver's side.

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Airbag Man bumpstop on passenger side.


Location Dowels

The rear spring packs sit on wedges, 10 mm thicker on the passenger side, and these are supposed to have a location dowel down their centre into a plate welded to the axle. However, on several vehicles it has been found that the dowel is missing; if the main U-bolts become loose, a wedge can move with such force that it shears off the four M6 cap-head bolts holding it to the axle.

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I have added the missing location dowels to the rear spring pack wedges on TT30. The dowels came from TravelTrucks. The idea was also to replace the thicker passenger side wedge with one the same as on the driver's side to stop the truck leaning to the right. However, despite adding a little Inox and letting it do its thing for 24 hours, and using an M6 Allen-key socket, I could not get one of the bolts holding the wedge to the axle out. I think I stuffed the head of that one so its there for the duration! No matter, the pin is in place (after a friend machined 0.05 mm off the diameter so it had a chance of going in under great pressure from tightening the U-bolts).

Much the same issues were experienced with the thinner wedge on the driver's side too. Its also there for the duration. I had to have 6 mm cut off the length of that dowel. It seems TravelTrucks expects you to replace the thinner wedge but I did not want it that way.

Inserting the dowels for the rear axle wedges required jacking up the body, removing each wheel in turn, undoing the U-bolts and letting the axle drop.

Reassembly – closeup of the head of the bolt holding the spring pack together re-entering the hole in the wedge. The dowel is already in the hole.

The axle had to be pulled to the front a little to allow the head of the bolt holding the spring pack together to re-enter the hole in the wedge.

Extra Front Spring

TT30 has been nose-down, causing drainage from the sink and shower to pool that way; the bed has had a discernable tilt to the front of the vehicle as well. Fitting an extra leaf to the front spring packs promises to greatly reduce the nose down. TravelTrucks was able to supply a kit of extra parabolic leaf springs, new U-bolts, and small wedges to correct for the change in drive shaft tilt.

The most difficult part of the job was jacking up the front of the vehicle so the spring packs could be removed. Fortunately TT30 has a tow point in the front bull bar and this is well anchored to the chassis rails. Removing the bull bar allowed an axle stand on a brick pile to take the weight (2100 kg) of the front.

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Removal of the front bull bar exposed the strong tow point.

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Axle stand on a pile of bricks under tow point; wheels off; axle dropped ready to remove spring packs.

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Undoing the U-bolts exposes the axle packing block with location hole for the spring pack.

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With the spring pack out, the spring keepers at each end must be removed by cutting away the rivets.

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The new spring is bolted to the pack. The keepers and small plastic separators are in place at each end.

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With the spring pack on the far side in place, the near-side pack is on the way out to add the new spring.

The supplied small wedges, thin end to the rear of the vehicle, are inserted between the spring packs and the axle packing blocks before tightening up the U-bolts.

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One end of a spring pack with new leaf below.

Reassembling the springs and U-bolts requires that correct torque settings are used:

Torque Settings
Wheel nuts (TT steel rims) 305 - 375 Nm
Spring pack U-bolts 116 - 142 Nm
Shock absorber lower mount stud 169 - 207 Nm
Spring pack end shackle bolts 212 - 258 Nm

After a brief run around the block to bed everything down, measured wheel arch heights in the front have increased from 1140 to 1210 mm above ground level on the passenger side, and from 1130 to 1190 mm on the driver side. That is, an initial height increase of about 70 mm.

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