70 FJ40

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Jul 13, 2012
Terra Firma
Hey all, new here. ;)
I've been reading a lot of stuff about the issues with my 40 and have learned a few things as well.

I'll start by saying I purchased my 40 with a Small Block 350, Turbo 400 in front of Toy transfer and drive train. 350's topped with an Edlebrock carb w manuel choke (if that makes a difference). Was bought in the PNW and ran without issues for a couple years until I moved to the 4 Corners area.

Issue #1 is overheating... details to follow:
Issue #2 is wobbly steering... details to follow:
Issue #1
When I moved to the 4 Corners it started running hotter than normal at low speeds/low RPM. Heating doesn't seem to be an issue in low range, it actually helps to keep the engine at normal operating temp (200-230). I consider 230 hot and start watching my temp guage and run over s*** I shouldn't but that's another story... :lol: Radiator has been rodded but when I replaced the thermostat I noticed a lot of scale buildup inside the intake manifold. I'm assuming, well no I'm not... I KNOW... that this scale needs to be removed for better heat transfer to occur properly but dont know how to do it (yet). I've currently got a "flex fan" and was told to replace it by a long time friend and 4x4 enthusiast and mechanic in order to improve air flow at low RPMs. I’ve also got a new high volume water pump waiting to be installed if need be.

Anybody have any idea about how to remove scale buildup from the engine block and attached components without taking anything apart? Is there a chemical that will do this that wont rot the block out?

I have a Reverse Osmosis water production setup so will be replacing the old tap/antifreeze mix in order to eliminate some of the scale buildup.
Can I flush the system real good with tap water then replace it with RO or DI water?
Issue #2
Steering... is kinda wobbly... Low speed driving is good but the death wobble shows up around 30-40 mph on pavement and the FJ40 follows the ruts bad like on unimproved roads.

This is what I've done so far... Complete knuckle rebuild (including ALL seals and bearings) and replaced most of the 11mm Steering arm and Trunion bearing plate studs/conewashers/washers due to stretching and stripping. I had a friend helping me and I worked on one side while he did the other side. I don't know if the shims were put back in place in the correct order and at that time I had no way of checking the preload on the trunion bearing. I'm thinking I may have to remove and redo all of the work on those knuckles so I can check it all out again and repair and/or replace anything that may be damaged. I also replaced all of the rod ends with brand new components from SOR (stock, I believe) and would recommend to anybody to replace the rubber TRE boots with polyurethane, especially in extremely dry climates. My rubber boots failed within a year so I'm happy the kit I got from SOR had spares included.

Recently, within the last few days, I've been reading and repairing my front end and had read that the shims that come with the MAF shackle reversal kit is supposed to face the fat end toward the shackle. My 4deg shims were installed backward according to this method so I reversed them and the steering got worse but the pinion angle was greatly improved. What happened?

One last thing; My relay rod? (from the pitman to the TR) is slightly bent and when I turn the steering wheel the tie rod pivots forward and backward which seems to be causing a lot of play in the steering. I tried straightening the relay rod but it’s still bent a little bit. Thinking I’ll try to find a piece of pipe to surround the rod with to increase the stiffness.

I'll be reading and reading and working and reading and reading and working and working till I get these issues resolved. :D

Any/all information is welcomed and appreciated and I'd be happy to share more when/if needed.

I almost forgot to mention that there's a little bit of cancer right at the body mounts right behind the front seats (yes it's both sides).

I've got a friend that's a body guy but I'm wondering if I'd be better off just welding in a couple pieces of plate steel, after removing the cancer of course?
12.5-wide tires will follow ruts much more than narrower tires - BTDT

have you checked caster angle ?
just remembered another issue...

My wipers motor (on top of the wind shield) wires doesn't match the wiring diagram in my Haynes manuel so I'm trying to figure out the correct wiring scheme. The Haynes manuel says the wires are purple with indicator stripes but my wires are BLUE with indicator stripes. Plus the wiring diagram for the early FJ40s in the Haynes manuel kinda sucks, it's difficult to read.

Anybody know where this wiper motor came from and how to rewire it?
I don't have any pics to post yet...
OEM wiper motor wires are blue with stripes

and, you might need glasses :hillbilly: I found the wiring diagram in the Haynes correct for a '72
12.5-wide tires will follow ruts much more than narrower tires - BTDT

have you checked caster angle ?

NO, I have not. I was was reading that the castor correction shims were installed backward (fat end forward) with the MAF Shackle reversal (w/stock length front shackle) so I switched them yesterday and the steering seems to have gotten worse.

When I first bought this rig the steering was loose. When I crawled under the front end I noticed that the aluminum caster correction shims were all but destroyed, leaving a 1/4in gap between the springs and the spring perchs, so I replaced them with the 4deg shims and tightened them up which greatly improved the handling.

Should I turn the shims back?
far as I can tell I had no issues with the pinion angle previously.

What's BTDT? (still trying to figure out all the acronyms)
been there done that

I had 12.5 tires when I got the truck - switched to 10.5 when I needed new tires
OEM wiper motor wires are blue with stripes

and, you might need glasses :hillbilly: I found the wiring diagram in the Haynes correct for a '72

Thank ya much...

I'll assume light purple means "Blue" then. ;)

I probably wont be getting any new tires soon but I'll keep that in mind when the time comes. In the mean time I'm going to remove the caster correction shims to see if it improves the handling.

Back in a couple hours. ;)
Cruisin4corners. Remarkable timing. I was just working on the wiper motor wiring this morning.
The 4 pin connector on the motor is a rectangle with a narrowed orienting key on one of the long sides.
Looking into the connector with the key section positioned downward.
Top left = blue no stripe = common, assume this goes to ground through the wiper control switch on the dash.
Lower left = blue with black stripe to center blade of wiper park switch.
Switched through contacts in wiper park switch through to the same brush that the solid blue wire goes to. I haven't completely figured out how the wiper park switch is supposed to work. It looks like it keeps the blue side connected to ground until a cam in the gearbox opens the contacts.
Top right = blue with red stripe = high speed.
Lower right = blue with white stripe = low speed.
I have a 7/70 and would recommend finding coolermans profile and links to his page. He's done a great job of going through wiring schematics and re-producing them for better referencing. His stuff has helped me a lot.
Cleg, Thanks for the info. I'll see what If these bad boys still work once I get 'em wired back up.

I removed the toyota wiring harness and installed a Painless harness. Those guys need to change their brand name cause that was a pain in the arse but at least it's done... Now to go match wires up sometime in the near future (not the priority at this point since I stripped one of the Ubolt nuts to hold the leaf pack to the spring hangars.
Checkin on coolermans page...

In the mean time.., I was tightening up the springs to the spring perches after rotating the 4* shim for my MAF shackle reversal putting the fat part forward in order to rotate the caster BACK to it's correct position when I accidentally stripped one of the 22mm nuts. So now here I am again... sitting and waiting for the weekend to end so I can get this darn thing replaced. Should I replace the U-bolts? I cant see any signs of damage to the threads but they may be stretched. 3 of them look like stock black u-bolts with one already replaced gold colored one.

I was doing a little more reading and my thoughts about caster were flipped 180 deg as well since I thought pos caster meant that the wheels inclined forward. So here's a bit of a clue in case somebody's going through this thread...

POSITIVE CASTER means that the caster axis is inclined toward the rear of the vehicle when compared to a vertical line.

NEGATIVE CASTER is when the caster axis is inclined toward the FRONT of the vehicle.

Hope that helps somebody in the future. ;D

That coolerman page is pretty cool. Wish I'd have found that a few years ago previous to my buying the painless BS.
general recommendation is to replace U-bolts due to stretching - a trailer place can make them for you if you show them one - that said, I have reused them when in a pinch

regarding with wiper motor wiring: when I did the Painless rewire, I left the OEM wiring to the motor that runs through the windshield intact and connected the Painless to it under the dash

also: it's easier to comment on caster if you measure your angle
Thanks DSRTRDR, I'll look for some new U-bolts then and will at the least replace the one that stripped the nut. Would like to have spares just in case but change is tight these days so will get what I can afford (hopefully all 4 of 'em).

The wiper wiring harness is just like you describe, with the original wires routed through the wind shield frame. Now I need to make the "painless" connection. ;)

Far as my caster angle goes, I don't have an angle finder gauge but I've got a protractor and a level and a level shop floor. The closest shop to me that I know would do this kind of work is an hour away.

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