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Winding it up

September 22nd, 2013

NOTE: For our Facebook readers, there are instructional photos included in this blog that Facebook will not show, please click on the above link to see the blog complete with photos.

One of the questions we are very often asked is about lifting the suspension. On Japanese trucks suspension lifts tend to be limited due to the independent suspension on the front end. When you take the front wheels off these trucks you’ll find no coiled spring, or leaf spring for that matter, the spring is slightly different, it is a bar, known as a torsion bar, the spring is derived from the twisting of the bar. The torsion bar runs from the lower wishbone back to a cross member somewhere near the rear output shaft of the gearbox (depending on make and model of course).

Now the torsion bar can be adjusted to wind up the suspension, there are pros and cons to doing this and we’ll cover these at the end.

This photo instructional was originally posted by the author in 2007 on Team Mudlark, it has been plagiarised and credited to other authors on certain forums since then but we have permission to reprint it here!

First job was to jack up the truck and put the axle stands under – had to put them behind the gearbox cross-member otherwise they’d get in the way of the job  Wink

Wire brush all the muck off the ends of the torsion bar bolts – then undo them completely

Measure them at the point where they are no longer under torsion:

Undoing and Measuring the Adjusters
Which worked out to be 60mm (this should be standard on all models)

Once the torsion bar is loose you then have to undo all 4 bolts on the gearbox cross-member – CAUTION only work on one side at a time and put the bolts back once you have finished that side!

Undoing the Bolts on the Gearbox Cross Member

Pull back the rubber gaiter on the front of the torsion bar

Pulling Back the Gaiter

The torsion bar will now pull out of it’s socket

Removing the Torsion Bar from it's Socket

Now index the torsion bar around – clockwise on the left hand side (looking to the front) and anti-clockwise on the right hand side (looking to the front)

The amount to index is calculated as follows:

Distance from pivot point to bolt/measuring point on torsion bar = 120mm

Distance from torsion bar to lower ball joint on wishbone = 400mm approx

Ratio = 3:1 approx which means every 1mm movement on the bolt moves the suspension by 3mm

So I indexed the torsion bar by 20mm allowing me a 60mm lift

Measuring  to get the Extra Lift
So the total amount is 80mm – note the jack used to lift the torsion bar into place and ease the pressure on the bolt while I was tightening it

Finally adjust the bolt so that the final measurement on the torsion bar is 20mm

Tightening up to Final Measurement

Last job is to refix the gearbox cross-member bolts and fit the front gaiter into place.

Repeat for the other side

Pros and Cons:

Pros:

It’s easy to do

Biggest pro is that it’s free – it costs nothing to do

 

Cons:

Once you have done it your steering geometry is going to be totally out – we need to look at the wishbones to understand this. With the front wheels off you will see the hub which is attached top and bottom to two arms which resemble wishbones and that is what we call them.

From the hub attachment to the point on which the wishbone swivels on the chassis you will see that the distance is shorter on the upper wishbone compared to the lower one, the reason for this is to try to keep as much of the middle of the tyre on the road when the suspension is forced up or drops down – example:  the wheel drops one one side (i.e. the chassis is lower on the dropped wheel side) the action of the wishbones pull the top of the wheel in towards the chassis causing the tyre to stay flat on the road even though the chassis is at an angle to the road. The wheel on the other side of the car does the opposite – the layout of the wishbones causes a reversed action.

So when you wind up the torsion you cause the wheel to droop angling the tyre to run on it’s inner edge, although this can (in most cases) be corrected somewhat, there is rarely enough adjustment to pull the camber (the angle that is affected) back to the original position

An additional effect will mean the tracking is out but this can be corrected to normal.

Although the cost of the modification is nothing, the result of the camber being out (if you can’t fully correct it) will mean that the tyre will wear excessively on the inner edge causing an early tyre replacement.

In addition with the hub now running much lower in relationship to the chassis you will find the constant velocity joints are now loaded close to, if not on, their maximum angle for normal driving. When the wheel demands more droop (when it’s articulating) the CVJ is going to be on breaking point – and yes they do break!

Finally many trucks have a bearing (usually a fine needle bearing) between the drive shaft and the hub, especially if there are auto or manual free wheeling hubs, this bearing allows the hub to spin independently of the drive shaft, the strain of a torsion bar lift will wreck  this bearing!

Conclusion: A cheap to do lift that will have long, and big, running expenses. Having said all that there is still a place for this lift for tweaking between 12 and 38mm after you have done a body lift – just to get that extra bit of lift to avoid rubbing on full articulation.

An Idle Moment

February 15th, 2012

Sims Hill

We were out laning around Newton Abbot a couple of Sundays ago we had quite an enjoyable day and then on virtually the last lane…

 

We’d just done this lane – it’s Sims Hill – when Arfer decided that he’d quite like to hug the hedge and headed for it so a stop and inspection revealed this

 

Broken Idler Arm

Broken Idler Arm

 

Broken Idler Arm

Broken Idler Arm

Seeing as the greyish bit was supposed to be attached to the muddy black bit, it was decided that the idler arm was broken, but with no spare – even if there were one have you ever changed one of these? Not a middle of nowhere job.

But we had to do something as being lose the idler arm tends to jam the steering on any piece of local metal – I had nothing in Arfer so a quick search of the lane came up with the ultimate answer…

Baler Twined Idler Arm

Baler Twined Idler Arm

 

Yep that good ol’ Devon Farmers stand by Baler Twine – fortunately this particular piece was pretty thick (for baler twine that is) and so I managed to tie up the idler arm and limp my way home – checking every so often to re-tighten or reposition the idler arm.

 

New Idler Arm Fitted

New Idler Arm Fitted

Well yesterday I picked up the new idler arm and today I fitted it and here it is in all it’s clean glory…

It won’t stay that way because we’re off playing this Sunday coming – hence the necessity to get it done 😀

I took some pics of the broken Idler as well:

This is the bit that broke - got a bit bent first

This is the bit that broke - got a bit bent first

 

 

 

 

 

 

 

 

 

 

 

 

The two pieces - notice the wear on the plate

The two pieces - notice the wear on the plate

No need for comments here

No need for comments he

This is not the first time I’ve had one of these break, last time I thought it was because I’d hit it on something, I’ve also bent one before as well and again I’d thought I’d hit it on something but this time I’m convinced that I haven’t hit anything, I haven’t done that many lanes since it was fitted in October – that’s less than 4 months ago – both the broken ones came from Milner Off Road and both broke within a short time of being fitted, the new one doesn’t and I’m hoping that it will last, but I’m wondering about reinforcing the idler arm, to put an additional lower bracket on to lessen the force delivered by Arfer’s big boots – talking of which: the special tracks are going on for the weekend – mustn’t get stuck must we 😀 😀

Adding A Sparkle

June 5th, 2011

The other day we were telling you about how Tilly, our 2.8 LWB Pajero, blew a head gasket and how she was leaking oil from the rocker cover gaskets. Well the result of the oil leak was a very dirty engine and engine bay – there was nothing you could touch without getting plastered in oil…

And that’s when we decided she needed an engine clean, we didn’t do it ourselves (which makes a change) we found a valeting service in Torbay to do it for us…

So last Saturday I went and met Steve of Steve’s Vehicle Valeting and left Tilly with him to have her engine cleaned…

By Hand!!!

Two hours later I returned to thisEngine bay 1

 

 

 

 

 

 

 

Engine bay 2

 

Engine bay 3

 

 

 

 

 

Even without seeing any before shots you can see the improvement!

I spent a while talking to Steve about the cleaners he uses and he demonstrated a few to me – a almost black, brake grime encrusted wheel became a shiny alloy in seconds (almost) under his administrations, he demonstrated the polish he uses on part of the bonnet and the screen cleaner on half the windscreen…

Guess I’ll be going back very soon to have the rest of Tilly valeted!

Heading for Trouble

June 5th, 2011

The other day I was talking to a guy about Tilly – Tilly, in case you didn’t know, is our 2.8 Mk2 LWB Pajero tow truck – we were talking about the usual things as one does around cars and trucks – you know the comfort, top speed, miles per gallon (or should that be metres per gallon?) anyway his last question was the usual “so going alright then?”  “Yes” says I “brilliant – no problems at all” then I made a joke of “Wood, wood where’s the wood” we both laughed as I drove off and I thought no more about it…

Until 2 days later that is, that was the next time I used Tilly, and it wasn’t long before I wished I had found that wood to touch. It took less than 2 miles for Tilly’s temperature gauge to hit the red, fortunately by a layby. Up went the bonnet and a quick squeeze of the top hose told me most of what I needed to know – it was hard, un-giving, not squeezable as it should be – a sure indication of a pressurised coolant system, so that was the end of that trip, and Tilly ended up back in her garage, but not before I did a block test on her, but she didn’t turn the block tester green as would normally happen with head or head gasket problems.

Now she was definitely pressurising the cooling system, and, as far as I know, there are only 3 causes for that to happen

  1. Faulty water pump impeller (if the impeller doesn’t turn and circulate the coolant then the coolant overheats and builds up enough pressure to blow the top of the radiator off)
  2. Faulty thermostat (this also can cause overheating and pressure build up in the cooling system)
  3. Cracked head or damaged head gasket

Now it was time to find out which of the above 3 was Tilly’s problem. First the water pump was ruled out as it was only replaced at the beginning of the year when the impeller came loose on the old one (due to lack of anti-freeze) and caused the top of the radiator to blow off! As we had tested for head problems and she’d passed that we went for the thermostat, so we took it out and tested it to find that it opened and closed quite well around about the temperature it was supposed to.

The thermostat went back in and we ran up the engine again and once more the cooling system pressurised. So we did another test with the block tester but it still stayed in the blue. So now it was back to basics, before we got the block tester, head problems were diagnosed by the following symptoms:

  1. Engine overheating
  2. Cooling system pressurising
  3. After taking the radiator cap off – revving the engine causes the coolant to flow up out of the radiator
  4. On tick over with a topped up radiator bubbles will come to the top of the filler

Tilly managed 4 out of 4 of those, so she had head problems. Now came the strip down.

As with all strip downs there are things you need to take off and others you don’t. With a 2.8 we are looking at the following:

  1. Remove the intercooler
  2. Remove the air hoses and air filter (I find the empty air box to be a handy storage place for nuts and bolts removed from the engine)
  3. Drain coolant system
  4. Remove top radiator hose
  5. Remove the bolts holding the pipework to the engine, the vacuum pipe can be removed from the vacuum pump and the small pressure hose removed from the fuel pump but the PAS pipework can be left connected
  6. We removed the bolts from the thermostat housing to facilitate easier removal of the solid cooling pipe between it and the head
  7. The manifolds stay on the head there are 2 studs and a bolt that connects the exhaust manifold to the turbo, these are undone
  8. The oil feed pipe to the turbo is connected to the engine block, not the head on the 2.8, removal is not needed
  9. Remove the wiring to the fuel pump, oil pressure switch and glo plugs (most sane people will have isolated the batteries before step 1)
  10. Remove the small coolant hose between fuel pump and top hose union
  11. Undo injector pipework and pull back from injectors
  12. Remove hose from injector fuel spill line
  13. Remove the oil pressure switch
  14. Remove the oil feeder pipe between the vacuum pump and the head, be careful you do not lose the copper washer from the head end down behind the fuel pump
  15. Remove heater matrix hoses
  16. Remove the 2 bolts holding the rocker cover and remove rocker cover (be careful – there is a small pot on the cover that contains oil which will spill all over the engine compartment if you don’t drain it)
  17. Remove the half moon gaskets at the rear and the front of the head
  18. Remove the chain tensioner from the side of the head
  19. Remove the bolt holding the chain sprocket to the camshaft WARNING – this bolt has a left hand thread
  20. Remove the sprocket from the camshaft, putting a cable tie through the chain will hold the sprocket safely in position (it is important not to remove the sprocket from the chain)
  21. Undo and remove the two front bolts on the head – these have a 12mm hex head and bolt into the timing chain cover
  22. Crack off the 18 head bolts in reverse order (the bolts are tightened from the centre outwards so undo them from the ends to the center) You may find that one or two of these bolts seem not so tight as the rest – make a note of where these are as they could point to the position of your trouble
  23. Completely remove the head bolts
  24. A soft headed mallet can now be used to loosen the head or a lever used to pry it up DO NOT PRY BETWEEN HEAD AND BLOCK you will damage the aluminium head
  25. Now the head is free you should be able to lift it off

There will be oil in the head still so make sure you have something on the bench or floor to soak up the oil – cardboard or newspaper is best – don’t use sand or sawdust until after you put the engine back together (both sand and sawdust are excellent for destroying engines). With the head upside down you can now check the face for hairline cracks – No cracks can mean a 85% chance (possibly more) of the head being ok, at the same time some cracking may not mean that the head is shot, to be 100% sure you’ll need to have it pressure tested – have a look for engine rebuilding engineers for that service. Many may advise a head skim as well, be careful here because the 2.8 head has ceramic inserts and they can’t be skimmed ask advice of the person that will skim it.

You also need to check the condition of the old head gasket, examine it carefully look at the condition around the waterways – some of the pockmarks in it will be caused by bits of the gasket having stuck to either the block or head. Look for track marks between cylinder and waterways, check the metal ring that runs around the hole for the cylinders – this was the problem on Tilly, one of them, Head Gasket Problem #1 cylinder, had split and it was this causing the problem the pressure was escaping through this split and then through the gasket material and pressurising the waterways, the gasket material acting as a filter to filter out the gasses that would have turned the block tester green

 

Head Gasket Problem 2Another giveaway was the bolts around the #1 cylinder on the right side felt looser than the rest when cracking them off and one had a trace of contaminated oil on the thread on removal.

Now let’s build the new parts list, although the head was showing cracks we were not too concerned with them, they were small surface cracks and not in places where they would be pressurising the waterways so our list was as follows:

  1. Head gasket
  2. Head bolts – Mitsubishi tell us that the head bolts can be reused up to 3 times and should be marked with a center punch each time it is reused – our head bolts had only been used once but were of unknown origin so we decided to replace them again
  3. Rocker cover gasket
  4. Front and rear half moon gasket
  5. Gasket cones for under the rocker cover bolts

Those last 3 items are very important if you want to keep the oil on the inside, Tilly’s half moons were hard and un-giving, like metal but brittle and both Tilly’s engine and engine bay have a coating of black oil on them – perhaps this is something that should be done every other oil change…

A few days later…

The spares duly arrived and with the head and block scraped clean of old gasket it was time to reassemble – we have the Mitsubishi workshop manual to follow, the Haynes head tightening sequence is a straight copy of this, however, had the head gasket come with it’s own tightening sequence we would have followed those (if a gasket company goes to the trouble to supply instructions then those instructions match the gasket)

Two things I hate with the instructions – one is to tighten a head bolt by bolt to 100Nm – I’ll always take it to 50Nm first then 100Nm, I see no point in attempting to warp the head by putting such uneven pressure on it the other is the two quarter turns – we spend years developing a tool that will measure torque accurately and what do the big boys do  – they tell us to give the bolt two extra quarter turns – they’ll be telling us to turn the truck on it’s side and jump up and down on a spanner next…

For the rest reassembly is the reverse of disassembly but remember that you have to reset the chain tensioner, do this by pushing on the end of the tensioner while prying the pawl away from the teeth with a small screwdriver then setting the hook to keep the piston in it’s closed position. Once you have the sprocket back on the cam shaft you can replace the tensioner and then with a longish screwdriver push down on the hook to release the piston allowing the tensioner to tension the chain – Standard warning: do not turn the engine backwards once you have done this or the tensioner will over tension.

Assembly is no real problem except the seals I obtained for the rocker cover did anything but seal, whether it was because they were too hard I don’t know, but sealant was needed as well and then extra sealant a day later when the seal still leaked. I shall be looking to buy genuine Mitsubishi ones the next time I take off the rocker cover!

Some afterthoughts:

We discussed some reasons as to why the gasket had gone:

  1. Faulty gasket – possible going to see how the replacement holds out
  2. Incorrect tightening of the head bolts – ruled out because the last gasket was fitted by us and we use a professional and certificated torque wrench
  3. Overheating – contrary to popular belief overheating in the first instance is usually caused by a component other than the head or head gasket giving way…

When we originally fitted a replacement head with a new gasket to Tilly it was getting into summer last year and antifreeze was the last thing thought of, in fact it was forgotten about until she overheated and blew off the top of the radiator. The cause was a loose impeller on the water pump (the coolant had frozen the impeller and when the engine had started it forced the pump shaft to revolve in the impeller hole) Then less than a fortnight later the alternator or drive belts (what was once called fan belts) broke causing yet another overheat. Both of these overheats may have possibly contributed to weakening of the head gasket causing it to fail about 5 months later…