DarkHorse's 1HD-T 80 Series 'Tank'


Active Member
I got hold of a 20t press to do all mine, there tight AF, made a big differance replacing them all with genuine


I got hold of a 20t press to do all mine, there tight AF, made a big differance replacing them all with genuine
Yeah, normally I'd have access to several workshops with presses... but not so much at the moment!

I've got a set of Drivetek rubbers for panhard and swaybar which I might try to do since they should be relatively easy. Radius arms might wait til I can get at a press.


Rego time has snuck up on me, and I'm going to get the old girl on historic/club plates this year (saving me something like $650/year for rego.) But, that means I have to get it inspected for roadworthy... which shouldn't be a problem except that it currently has no driveshafts, no fan or shroud, and only half a power steering system. So that has all shot up the priority list for this week.

In preparation for doing the steering box rebuild tomorrow I popped the pitman off ($50 puller did the job. Not easily, but it's off) and cracked all the bolts on the outer housing, just to make sure I wouldn't get held up by anything seized. They all came loose reasonably easily (2ft breaker bar also paying for itself!) but the 10mm Allen bolt for the power piston - not so much. Despite liberal application of Inox, heat, and rattle gun, she's rounded out:

I'm guessing my best bet now is to weld a nut onto it? Open to any other ideas.


Did the steering box today, thanks to the walk-through on IH8MUD.

I think I stumbled on all the usual issues:

1) pitman took a bit of grunt, but a proper beefy puller and 2ft breaker bar did the job. If you don't have a vice consider doing this on the car so it's held in place.

2) Plunger guide nut is just a horrible design. Solution was a nut welded on, as there wasn't room between the raised casing and the base of an allen key to get a rod in:


3) input shaft preload was too tight when I got the locking collar back to my marks. Tapped it back off 1mm, keeping the actual cap lined up, and it freed up.

4) worm gear balls are a proper pain. Took a good couple of hours. No such thing as too much lube. I think I got them all in... but what magic stops them spitting out the top of the piston on extension?

5) teflon ring inside rubber o-ring is tricky. Eventually got it with the heart-shape method.

6) shaved the teflon ring on re-insertion. Tiny sliver. Going with it, but I'll keep the original in case.

Now to weld up the chassis so I can put it back in!



New toy arrived today:

Supercheap Auto special was too god to pass up. Matches my 170hf stick/tig unit. ;)

Sooooo... here goes nuthin! Cleaned up the chassis rail, and drilled a 3mm hole at the end of the two cracks:

Then used a cutting wheel on the Dremel to groove out the cracks:

Ready for welding, grinding, then plates tomorrow (if the weather holds.)

I cleaned up the inside as best I could. Bunch of stuff in the way of getting tools in there. It'll be OK... it's clean of any dirt, rust, oil etc, just paint still there.

I also got the poly bushes out of the panhard. Tried to clean and linush to get the new rubbers in, butnot sure I'll be able to without a press.


OK, finally had a crack (pun intended) at the chassis today.

Welded up the two stress fractures, and beefed up the panhard bracket seam and tube cross-brace:

Ground them flat, then since I was on the outside, did that plate. I could not for the life of me get the MIG dialled in - during a single run it would vary from the hissing burnback of insufficient wire speed to the staccato tapping of too much wire. Likely not helped by the voltage drop over 30m of extension lead I had to run. On top power setting it would trip the power board after about an inch, and with that removed it would go into overheat protection after maybe four inches.

So results were certainly not as pretty as I'd hoped, but it is well stuck on there:

And doesn't look as bad under a coat of flat black:

The inside plate was a whole other level of pain - literally. Spitty welder raining molten steel down while you try to contort yourself to get eyes and gun around diff, alternator, oil pan etc... and with the light fading I admitted defeat and called it before I got so angry that I broke something or hurt myself.

I'm a little worried about what fresh eyes will find in the morning, but that's tomorrow's problem.


Well-Known Member
It might not look the prettiest but keep in mind the original lasted 20+ years so that will last out the rest of the car, another 20 years from now none will be driving our old oil burning 4wds unless its some type of combustion engine historical meeting :eek:


It might not look the prettiest but keep in mind the original lasted 20+ years so that will last out the rest of the car, another 20 years from now none will be driving our old oil burning 4wds unless its some type of combustion engine historical meeting :eek:
I might have upgraded to a 105 series by then... ;)


I might have upgraded to a 105 series by then... ;)
...and started this whole process again, just with more wires...

Another trying day today with uncooperative welder, awful ergonomics, and howling wind just to make it even less likely that I achieve anything presentable.

Got the inner plate to the point where doing any more was making it worse instead of better. Ugly as sin, but definitely attached, and I don't think I am in any danger of over-penetrating/heating the chassis tube:

Again, slightly better with a shot of flat black:

The really heart-breaking thing about this is that I am a better welder than that, and I held off on this job for ages until I had the time etc, so the results are really disappointing.

Then the wonderful feeling of finally bolting clean stuff back on. Steering box, lines, pitman, tie rod:

High-pressure line back in it's brackets, and new low-pressure line run along side - will be tidied up when finalised:


Low pressure line excess waiting to be snipped for cooler, and new dampener bolted up:

List is still pretty intimidating:
  • Align steering
  • Grease balljoints
  • Install cooler
  • Tidy lines, fill, bleed

  • Install driveshafts
  • Rebush & reinstall panhard
  • Fab speed sensor brackets for cruise control

  • Install radiator hoses
  • Flush & refill cooling system

  • Install fan & shroud

  • Re-plumb vac feed for cruise control to vac reservoir instead of booster
  • Bolt check everything I've done
  • Sort out why horn not working
Then maybe standard service stuff, roadworthy, and club rego.
Last edited:


Doing some research last night, and I think I've worked out my major mistake with the welder - apparently MIGs, especially low power machines like mine, really don't go well with pure argon. I have a bottle of pure argon for TIG work recently, and was really hoping not to have to fork out for another bottle of MIG mix, but looks like I am going to have to with the trailer build coming up.

Good lesson learned anyway. I may revisit at least the outside and just tidy it up a bit... or I may not. It really don't look too bad unless you're really looking for it.


Some minor progress today, but any movement is good psychologically.

Driveshafts bolted back in.

Panhard bushes pressed in and a quick splash of paint.

Rough steering alignment done, though not finalised given lack of panhard.

Steering cooler finally arrived. This thing is a whole lot bigger than I expected, so hopefully doesn't look too ridiculous sitting on the front chassis rail:

If the weather improves I'll suss out bracketry and get it mounted and plumbed up.

That's kind of the last missing piece, so now I can get everything assembled and off for roadworthy.


Few more baby steps today...

Panhard back in, with a bit of creative jacking and a ratchet strap from one side of the chassis to the opposite side of the diff:

Cruise control vac line teed into the feed from the pump to the reservoir:

After looking at a million parts diagrams I still couldn't be sure exactly where the non-return valve for the brake booster was (built into the res, or the booster?) so figured this was the safest option. Vac hose runs neatly along the top of the firewall to the actuator:

Also got the power steering cooler mocked up (that thing is hoooooge) so I can make a bracket, and muscled the car away from the kerb so I can do a rough alignment and fill/bleed the steering system.


Another frustrating afternoon fighting with welders - I don't have pure helium so HF TIG on Aluminium doesn't work. Thankfully pure Argon for MIG does... sort-of. So while again I am not proud of the results, and I'll spare you the ugliness on the back, the PS cooler is finally ready to mount:

Because that took four hours instead of four minutes I didn't get anything else done... which in turn means I won't get anything done until I'm back from work on Friday, so can't get roadworthy done before the rego expires.



Active Member
[QUOTE="DarkHorse, post: 649783, member: ]I don't have pure helium so HF TIG on Aluminium doesn't work. Thankfully pure Argon for MIG does... sort-of.
Are you sure? Most people TIG ally with pure argon, myself included (not particularly well mind you)

Great work giving it a birthday, keep it up!


Are you sure? Most people TIG ally with pure argon, myself included (not particularly well mind you)

Great work giving it a birthday, keep it up!
Not sure of much when it comes to TIG - it's all very new. I've managed to at least get something happening with both mild and stainless steel, but this was the first time trying ally.

I tried with pure Argon, and it wasn't having a bar of it. Plenty of heat, but no puddle so the metal would just cave in on itself before I could do anything with it.

Are you using DCHF or AC?

That said the torch was having other issues - I had to 'hotwire' the trigger because a wire had come loose in the plug...


Still feels like baby steps... but progress is progress...

Cooler is mounted and sits really nicely all plumbed up:

Steering system filled and bled, balljoints greased, and all seems happy and smooth from lock to lock. I think I might be one spline out reconnecting the input yoke on the box, but I've fudged that out with adjusting the tie rod. Rough string-line adjustment is done, and I'll get a pro alignment done when I can.

Apparently bottom radiator hoses for an early 80 series are problematic... here is what I've been through:

Top is what came off the car. It's a Gates hose, judging by the remnants of the label from under the clamp, but a part number hasn't survived, and it's been cut down at one end, so obviously didn't fit originally anyway. Middle is for an FT/multivavle/95-96 80 series... which you'd think would be identical but really really isn't. Bottom is for a 1hz 70 series, but at least it's close enough that it works. So after all of that I still haven't seen the correct part for a 1hd-t 80.

Anyhoo... radiator hoses and fan are back on, and I double tasked while the PS was bleeding and put a rad flush through the cooling system. That's now draining and I'll refill with coolant tomorrow.

Otherwise, to have it driveable I just need to throw the fan shroud in, though I'd also like to get the speed sensor for the cruise control sorted before I go away again on Monday. Then next week I can sort alignment, roadworthy, and club rego (I've ended up just forking out for full rego in the meantime, but that's refundable when I get it on club plates.)


OK, it's all bolted back up, checked, run and test driven:
- coolant flushed, new rad hoses, system bled
- steering aligned (kerbside stringline job, but feels OK) cooler is shedding heat, and no leaks
- all bolts checked, splash guards bolted back on
- new trailer plug installed
- new starter relay (genuine) which seems to have fixed that problem, and a new horn relay (aftermarket) which has not.

Haven't got the cruise finalised yet, but that and the horn are about the only things from that list a few posts up. The horn is annoying me, because I could put my multimeter on connections at each point in the chain and get 12V when the button was pressed... so I figured sticky relay was the culprit. New relay, no joy, so not sure now.

I ran it for a few mins to get everything up to temp and checked for leaks. All looked good so I drove it around the corner to a servo and checked tyre pressures and also checked everything again. Happy enough with that I went for a quick blast up the freeway to get it to 100kmh and see how everything felt. Idle felt smoother looking at the motor and sitting in the seat, and low speed driving didn't feel as vibey so I think at least one of the motor mounts was shot. Annoyingly most of the noise still happens up around 100kmh, but I don't feel it as much through the steering - so hopefully box rebuild, balljoints, dampener and panhard is doing some good. Most of the issues at speed feel like they're coming from the back end.

Anyhoo, happy enough that it's all back together and no worse than when I started I took it for a wash to remind myself that she's actually not in bad shape for an old beater...

I'm in Ballarat a few days a week for work at the moment, which is delaying working on the car and the rego process, but I'll take the trailer out there and make the most of the workshop facilities to get that job done.
  • Like
Reactions: CTL


Drove the 125km to and from Ballarat this week, and car was much happier for the run. Aside from a slightly heavier feeling throttle (likely my inaccuracy remaking the linkage) and a sketchy feeling under heavy breaking (hopefully because of my dead-straight kerbside alignment instead of the factory 3deg toe-in) it felt much smoother and tighter.

A couple of cold morning starts unfortunately revealed that the new relay had not solved that problem, so solenoid contacts are the next resort. Kit has been ordered.

I've also got an intermittent hi-beam switching issue, so have replaced the headlight relay. I'm running all the headlights off seperate relays, but using the factory plugs as switching signals, so a faulty relay could still be causing the problem.

Electrical gremlins are getting boring!
Last edited: