Hilux MK6 Chassis and Rear Tub

[Jelly_Sheffield]

Finally got back from the middle east and had a chance to get on with this today.

No photos as I was in a hurry to get on with it after being delayed.

For anyone coming after me, I have made some notes

Procedure:

- chock front wheels, jack up both rear wheels, and get the vehicle on stands, my truck is about 5" higher than stock (between tyres and suspension) and I only barely needed the wheels off the ground to have enough space to work, on a stock vehicle you would probably need more height.

- Remove the rear wheels, "Eyebrows" and inner arch covers from both rear wheels.

- Remove the filler neck assembly.

- Siphon the fuel out of the tank

- Remove the fuel tank protector from the straps.

- put a jack under the tank and disconnect the straps at the passenger side, in theory they unbolt, but in practice it's likely you'll have to cut them off, a metal blade on an oscillating multi-tool is the only way I could do this without risking damage to the tank.

- using the jack slowly hinge the tank down until you can disconnect the fuel lines and sensor wiring.

- Then fold back the self adhesive rubber and lift the wiring loom and fuel lines out of their channels, remove any remaining wiring clips.

- fully drop the tank and pull out of the straps,

- if you cut the straps off, you can now remove the pins holding them under the center and detach them for replacement, you can also safely attack the strap bolts with a gas torch in an attempt to remove them... Not that it will help.

- disconnect the midsection of the exhaust and cut off the two supports on the fuel tank cross member going to the exhaust rubbers.

- Remove the drivers side rear shock.

- taking care around the wiring loom and brake lines, cut off the fuel tank cross member with a recip saw on the passenger side, as close to the chassis rail as is practical

- on the drivers side cut it off next to the exhaust bracket you chopped, if you cut at the chassis side it will destroy a reinforcing plate you want to reclaim to save work.

- thoroughly needle scale and wire wheel around the welds that originally mounted the cross member so you can see how it was attached.

- make reference marks with a punch or soapstone to help align the new cross-member later

- disconnect the battery and alternator.

- plasma gouge (or grind) the welds off gently to remove the remaining bits of cross-member.

I will add the rest as I work it out tomorrow evening.

 

[Jelly_Sheffield]

Parts Required

(based on a single-cab KUN25R, double-cab and KUN26R owners should run their vin on https://toyota-europe.epc-data.com/ and double check the parts diagrams)

At a minimum you will need:

• CROSSMEMBER SUB-ASSY, FRAME, NO.5 (Toyota Part № 51205-0K030)

• 2 off EXHAUST GASKET, STD PART (90917-T6002)


It is likely you will need:

• BAND SUB-ASSY, FUEL TANK, NO.1 (77601-0K090)

• BAND SUB-ASSY, FUEL TANK, NO.1 LH (77602-0K080)

• 4 off EXHAUST CONNECTION NUT, STD PART (94185-61000)

• 4 off EXHAUST CONNECTION BOLT, STD PART (90105-T0095)

• 4 off FUEL TANK GUARD, FLANGED NUT, STD PART (90179-08241)

• 2 off BOLT, FUEL TANK (77644-35030)

• 2 off BOLT, FUEL TANK MOUNTING, STD PART (90119-T0205)

• BRACKET SUB-ASSY, FUEL TANK MOUNTING, REAR (58062-0K010)


If You are Particularly Unlucky you will need:

• REINFORCEMENT, FRAME NO.5 C/MEMBER, RH (51257-0K010)

• PIPE SUB-ASSY, FUEL TANK INLET (77201-0K100)

• BOLT, FUEL TANK INLET, STD PART (90105-T0204)


Toyota are not actually too bad price wise for any of these parts, so if the lead time isn't terrible, it can actually be worth ordering the lot directly from their dealer parts counter.

But knowing the OEM part number helps track down pattern parts as well if you want to go that route.

 

[Jelly_Sheffield]

Chucked a couple of hours at this after work, and got everything tidied up apart from the reinforcement bracket I was looking to reclaim, so should be able to tidy that up tomorrow and weld it all up.

There's a lot of space to work under there, I can happily sit cross legged with my back resting on the prop shaft wearing a visor and ear defenders...

Properly bounces the sparks around though, I have somehow managed to direct a large quantity of grinding sparks down the back of my neck, which will be delightfully itchy tomorrow.

 

[Jelly_Sheffield]

So it's now structurally repaired, but I got rained off before I could complete the reassembly.

There's some photos from a mate who popped over to help me get it positioned (would be do-able but very difficult using clamps if you were working solo) and then hung around to chat and pass things to me whilst I was welding it up.

I have welded up exactly as Toyota did at the factory, so on the outside it's a fillet at the top only.

I debated welding all round here to reduce future water ingress, but as it's welded on the bottom of the chassis rail and all round on the inside, I presume there's a good reason for omitting those short sections.

I used the small holes left behind at the outside corners to inject Waxoyl, which will hopefully prevent a repeat of the previous corrosion

Tips for future repairers:

Everything will be *so much easier* if you have a welding torch with a flexible, or adjustable neck.

It would be doable with a standard torch, but the flex-neck makes it much easier to see, even so there's points at the end of certain welds where you're going to have to finish that weld by Muscle Memory and Sound alone, then inspect afterwards.

This is the reinforcement plate on the drivers side you want to reclaim, as they're currently on a 3 month backorder with Toyota UK, and no pattern parts exists.

I will try to get a photo from. The underside of the truck tomorrow showing how it's assembled.

In practice the only way to save it is to plasma/oxy gouge the weld on top of the chassis off very gently, then cut the crossmember away round it, then cut the remaining bits of the crossmember off the chassis with a torch.

At which point the whole thing comes off and you can use a grinder and chisel to get the crossmember reminents out of the now detached reinforcement plate.

Only using a grinder it would be impossible to save this plate without grinding into the chassis rail, so you'd need to order a new one, or allow time to reconstruct it from the pieces / fabricate an equivalent one from 3mm plate.

Without access to a lift, this is by far the best position to do the inside front and bottom welds.

Note the strategical positioned welding jacket... In spite of that precaution when welding the other side I shifted my weight, which moved the jacket just enough to let a droplet of molten metal past, which promptly burned through my overalls, rugby shorts, and boxers, leaving a tiny burn on my upper thigh.

To do the top and rear inside welds, the best option is to drop the spare wheel and reach over the axle from the back.

You can just fit in with a standard helmet on (a monkey mask would really help) and once in you will get a really stable position with one arm resting on the spring and the other on the diff...


Note also tomorrow's job featured in the last photo, it would pass the MOT with duct tape over it... But not fixing it will make it much harder to refit the wheel arch, mudguards and eyebrows, which are required to pass due to the width of my tyres.

 

[Jelly_Sheffield]

So the bodywork was a right ****.

The apparently fine front section of the wheel arch had much worse rust than the gaping hole at the rear, so a huge section had to be replaced.

Started out pretty well, with making up the flanges that the arch covers and eyebrows fit on to.

Plasma-ed it out for some 3mm and bent to shape using the curve of the opposite side as a guide.

The square holes for the clips were a pain, but I managed to do them with the plasma and a bit of filing, they're not perfect but they're in the right place.

Fitting was easy as I had plenty of decent parent metal to weld to at key reference points and once in the whole tub immediately regained a load of rigidity, despite the gaping hole.

Doing the front however was a different story...

 

[Jelly_Sheffield]

Immediately on trying to trim the reminents of the old flange, everything began to disintegrate, leaving it disconnected from the chassis mount, and just floppy.

I managed to tack it in approximately the right spot, then make a cardboard guide to bend it into position.

Then began patching...

Two issues, first the 2mm steel I thought I had for this, was in fact 1mm, not so easy to work with.

More importantly whilst the parent metal where I cut out was fine, attempts to bend it I to shape revealed it was rusted out further back.

So suddenly it becomes a patch on a patch job...

At this point the tub had lost so much rigidity that it was near impossible to grind back the paint, so I gave up and welded through it...

The very 3D shape also caused bizarre movement due to shrinkage so the fit-up became progressively worse as I went on.

Welding it up took hours and the result looks like absolute crap.

Ultimately it's in, it's strong, and will do... At least for the MOT I will give it a buzz with the flap disk and add some cold galv and stone chip.

However, long term if I don't go ahead with replacing the tub, I think that's "scaffolding" that gives me enough structural rigidity to cut logical shaped sections of this repair out and re-plate the whole thing neatly in 2mm zintec.

Given the initial situation I think any repair to that area done by someone of my (lack of) skill level with body work was destined to be a ****-show... I guess I know more for next time.

I lost the light before I got time to do the rear patch although that's tacked in place ready to finish tomorrow evening.

 

[Jelly_Sheffield]

Bonus Round:

The truck is clearly fighting me hard on this, as I have somehow acquired a 3rd degree burn on my arm.

I remember it briefly hurting like hell when I brushed past something hot, but it stopped hurting enough to register with me pretty quickly and I assumed I'd moved away in time...

Apparently not, it just killed most of the nerves.

Just finished debriding the burn with Iodine and saline to get all the grinding dust and fibers from my overalls out of it (which stung pretty bad all round the edge) will pop a dressing on it overnight then go get some proper burn dressings from the village pharmacy tomorrow.

Hopefully it won't get infected!

 

[OJCar]

There was me thinking only Land Rovers rust ...

 

[Jelly_Sheffield]

There was me thinking only Land Rovers rust ...

Land-Rovers rust from the most critical structural elements outward...

Toyota's allow the body and ancillary parts to rust themselves clean off of the chassis.

Who's to say which is the better approach?

 

[Jelly_Sheffield]

Lost a bit of time this evening taking the cat to the vet, but still had enough light to do the last bit of body welding.

That went in lovely by comparison to the bear-fight I had on the other side.

The fuel tank brackets are back in, and the exhaust midsection back on it's rubbers and bolted to the downcomer with a new gasket.

The tailpipe flange however disintegrated when I went to drive out a rusty bolt, so that needs replacing.

In a moment of frustration turning to desperation, and possibly madness, I made up a template and plasma-ed a flange out by headtorch, drilled the holes to the correct pcd and rouged out the main hole with a die grinder.

I guess nothing ventured, nothing gained if it doesn't work I can always order a new tailpipe, or a set of flanges.

But I really want this back on the road now.

 

[Jelly_Sheffield]

I kept going... The fuel tank is now about 2" away from being back in position but I have had to give up.

The design of the fuel tank mounting is a nightmare to work with because without a lift you have to be lying under the jacked up tank to get the two pins that secure the straps in.

Any attempt to put the pins in first is impossible without removing the rear propshaft to make room for the tank to slide in diagonally.

That said, on a lift, with a transmission jack, it would be child's play to install.

 

[Jelly_Sheffield]

Chucked an hour at it in my lunch break and was very productive.

Got the exhaust back on, the fuel tank secured, and quickly did the front nearside anti-roll bar drop-link (needed for MOT).
______

There's a real knack to doing the fuel tank:

1) remove the filler neck bracket bolt.

2) slide the fuel tank under the vehicle.

3) somehow lift it enough to fit a big trolley jack under each end... if you have a third put one under each front corner and skip step 4.

4) jack it up high enough to get a bottle jack under the front outer corner, then precariously balance it whilst you move the front trolley jack to the front inner corner.

5) jack it up until it's at least ⅔ of the way in, and awkwardly reconnect the fuel and return lines and fuel sensor, then fandangle the wiring loom and tubes under their respective grooves. Don't forget to flop the protective sticky rubber flap over them when you're done.

6) slide the tank straps under the tank between the jacks, put the two pins and clips in your breast pocket.

7) go round to the back and crawl under till you're reaching over the diff, take a pin out of your pocket, grab the rear strap and wiggle it into place round the tank, the get it lined up in the crossmember and insert the pin.

8) take the retainer clip out of your pocket and fit it onto the pin before you forget.

9) go round to the far side from the tank, crawl under the exhaust facing upwards, and repeat steps 7 & 8 with the front strap and clip, fitting into the fuel tank outrigger.

10) go back to the fuel tank side, and slowly jack it up until it almost touches the crossmember at the back and outriggers at the front.

11) grab the the bolt for the strap (if you lost or destroyed the old one, it's M10×1.25 [fine pitch] and must be between 35-40mm long), and the appropriate ratchet.

12) grab the rear strap by the hinge and pull it towards you hard with one hand until the hinge lines up with the hole in the bracket, hold it there and with your other hand insert the bolt and begin to thread it in, as soon as it takes get the ratchet on it, and get 2-3 threads of engagement before you let go of the strap.

13) repeat step 12 but at the front, there's room to get a 3/8 impact in here which is much easier as long as you're certain not to cross thread the bolt.

14) with the tank still slightly loose, get the two hoses back on the filler neck and vent line, and tighten their clamps up (It's nigh on impossible later, that last 1½" makes all the difference).

15) fully tighten both bolts up, to pull the tank into place.

16) reinsert the fuel filler neck bracket bolt and tighten it to the chassis.

17) fit the tank guard to the 4 bolts on the straps.

18) refill the tank with fuel.

19) pop the bonnet and pump the little button on top of the fuel filter to re-prime the system, it will take 40-50 pumps to fill completely.

20) enjoy a deep sigh of relief.
_______

There's also a trick to the front drop link, such that you don't have to disassemble the strut to fit it (which is Toyota's official repair procedure).

1) Don't even bother trying to undo the nuts on it with UK corrosion your chance of getting the hex in the bolt to hold is near enough zero, so angle grinder them straight off on the drop link (i.e. not nut) side, beware access is poor and you're right next to the ABS sensor wire.

2) Drive the remains of the bolts out with a punch.

3) get a small bottle jack and place it on top of the sway bar, then extend it upwards until it fits securely inside the hollow V-shape in the pressing of the upper control arm, as per the image:

N.B. It's critical you get the top of the jack in that notch, or it won't be secure, and the whole thing goes from "well this is a bit sketchy" to "I'm definitely going to launch a bottle jack into my face with a big spring any moment"...

Wearing a visor if you have one might be wise just in case.

4) Gently jack the sway bar down a little way.

5) with the drop link lined up in the position it will eventually go in, flex the ball joint on the bottom half of the drop link (that fits the sway bar) as far as it will go towards the front of the vehicle.

6) rotate the drop link so it's lying flat pointing towards the front of the vehicle, and get the bolt on the bottom into the hole on the sway bar at an angle.

7) slowly jack the bar down whilst gently pushing the bolt in... There an extremely narrow window where it will just pop in... not far enough it's at too big an angle to slide in, too far and it fouls on the steering knuckle.

8) as soon as it pops in, get a nut on it loosely.

9) get the upper bolt lined up into the hole on the steering knuckle, and gently push in.

10) very slowly release the jack, the upper bolt will pop into place almost as soon as the jack starts to release pressure.

11) get a nut on that loosely too.

12) remove the jack.

13) tighten the two nuts up with a 17 or 19mm ratchet ring spanner (varies depending on parts supplier, OEM is 17, but 19 is normal aftermarket) and a H6 hex key (or impact hex bit) to stop the bolt rotating.

14) torque to spec using a crows-foot and the aforementioned hex key.

15) feel very smug about how quick that was, and how many crusty high-torque bolts you avoided having to undo.

(It took longer to type these instructions out, than it did to change the drop link).

 

[Jelly_Sheffield]

Ground back and sprayed with several layers of cold galv and stone-chip, the body repairs don't look all that bad.

That rear one blends in pretty nicely, and with some filler and sanding could probably be made to disappear.

The front is less good.

Although, with filler and paint it might still be good enough that I could blend the distortion into the general body dings that it's had since I acquired it.

MOT booked for tomorrow at 10am, so hopefully it passes without finding anything else amiss.

 

[OJCar]

MOT booked for tomorrow at 10am

Good luck !

 

[arther dailey]

So it's now structurally repaired, but I got rained off before I could complete the reassembly.

There's some photos from a mate who popped over to help me get it positioned (would be do-able but very difficult using clamps if you were working solo) and then hung around to chat and pass things to me whilst I was welding it up.

View attachment 463321
I have welded up exactly as Toyota did at the factory, so on the outside it's a fillet at the top only.

I debated welding all round here to reduce future water ingress, but as it's welded on the bottom of the chassis rail and all round on the inside, I presume there's a good reason for omitting those short sections.

I used the small holes left behind at the outside corners to inject Waxoyl, which will hopefully prevent a repeat of the previous corrosion

Tips for future repairers:

Everything will be *so much easier* if you have a welding torch with a flexible, or adjustable neck.

It would be doable with a standard torch, but the flex-neck makes it much easier to see, even so there's points at the end of certain welds where you're going to have to finish that weld by Muscle Memory and Sound alone, then inspect afterwards.



View attachment 463333

View attachment 463334

This is the reinforcement plate on the drivers side you want to reclaim, as they're currently on a 3 month backorder with Toyota UK, and no pattern parts exists.

I will try to get a photo from. The underside of the truck tomorrow showing how it's assembled.

In practice the only way to save it is to plasma/oxy gouge the weld on top of the chassis off very gently, then cut the crossmember away round it, then cut the remaining bits of the crossmember off the chassis with a torch.

At which point the whole thing comes off and you can use a grinder and chisel to get the crossmember reminents out of the now detached reinforcement plate.

Only using a grinder it would be impossible to save this plate without grinding into the chassis rail, so you'd need to order a new one, or allow time to reconstruct it from the pieces / fabricate an equivalent one from 3mm plate.



View attachment 463337

Without access to a lift, this is by far the best position to do the inside front and bottom welds.

Note the strategical positioned welding jacket... In spite of that precaution when welding the other side I shifted my weight, which moved the jacket just enough to let a droplet of molten metal past, which promptly burned through my overalls, rugby shorts, and boxers, leaving a tiny burn on my upper thigh.




View attachment 463339

View attachment 463340

To do the top and rear inside welds, the best option is to drop the spare wheel and reach over the axle from the back.

You can just fit in with a standard helmet on (a monkey mask would really help) and once in you will get a really stable position with one arm resting on the spring and the other on the diff...


Note also tomorrow's job featured in the last photo, it would pass the MOT with duct tape over it... But not fixing it will make it much harder to refit the wheel arch, mudguards and eyebrows, which are required to pass due to the width of my tyres.

I am hoping its not just trolley jacks saving you from being a squashed tomato.

 

[Jelly_Sheffield]

I am hoping its not just trolley jacks saving you from being a squashed tomato.

Two big 4T axle stands cradling the rear axle, which in the vast majority of photos I managed to obscure with tat.

The trolley jacks were for lowering the fuel tank out, and won't actually reach the chassis rails on the truck, I use a 25T air over hydraulic bottle jack to raise and lower it (which is delightfully lazy).

 

[Jelly_Sheffield]

Good luck !

Alas, I Have the luck of Jonah!

Somehow on the drive from my house to the test centre the NSF CV Boot failed, spectacularly, and the test was otherwise fine with no minors

Moreover after waiting the full 90 minutes for this news due to an MOT auditor, the chap on the front desk at the garage (not the same one as last time) was dead shirty with me for asking to see it on the ramp, as I couldn't understand how it failed on that having been in there and checked it less than 24 hrs previously.

When he eventually agreed, I took one look and went "yeah, that's proper **Language**ed, thanks for showing me".

 

[OJCar]

That's cars for you!
Lavish attention on them and do they respect you for it ...

 

[Jelly_Sheffield]

That's cars for you!
Lavish attention on them and do they respect you for it ...

Just like the cat, who has been meowing at me for attention whilst I eat lunch, then as soon as I went to play with him, decided to go take a nap.

At least the cat cares about me, even if he does demonstrate it by licking my moustache...

 

[arther dailey]

Alas, I Have the luck of Jonah!

Somehow on the drive from my house to the test centre the NSF CV Boot failed, spectacularly, and the test was otherwise fine with no minors

Moreover after waiting the full 90 minutes for this news due to an MOT auditor, the chap on the front desk at the garage (not the same one as last time) was dead shirty with me for asking to see it on the ramp, as I couldn't understand how it failed on that having been in there and checked it less than 24 hrs previously.

When he eventually agreed, I took one look and went "yeah, that's proper **Language**ed, thanks for showing me".

thats a posative though as none of your work was mentioned eh.