New 712m owner + first things to check

[satosh]

I picked up a 1973 712m recently that is in great condition. Prior owner kept everything original with no mods aside from fuel injection. No off roading as it was sort of a show car. No rust. Runs great. Likely sat for a few years before being sold/started occasionally. Occasional backfire issue when going from 1st to 2nd and 2nd has a tendency to lug right when going into it but aside from that all seems good.

As a newcomer on the scene what areas should I focus on first? I’d like to feel confident enough with it to go on multi day over landing trips with my son. thanks!

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[rmel]

Welcome to the forum and congrat's on a nice looking 712.
Please add your location to your profile.

First, was the PO a member of this forum, if so you might be able
to look for any posts of interest about this truck.

In general, assume nothing has been done w.r.t. maintenance for some time.
It's good to start from a clean slate and run through the complete maintenance
schedule then you know where you are. Although you mentioned this rig is a EFI
conversion, which is far from routine. You may want to get some details on
that as to when it was done and if done by Jim LaGuardia of Goatwerks.com.
If so Jim may have a lot of info for you on maintenance and the condition of
the running gears.

If the truck did not come with the maintenance manuals, get them ASAP. But
for starts, if not done recently -- change all your fluids ALL. Diff''s, Tranie, X-case,
Portals, Engine, and hydraulics and air/fuel filters. Tricks and tips can be found
using the search function. Take a PIX of your EFI setup showing the fuel rail and
vapor reservoir, you may also have the hotter cam installed. Make sure you use
dino oil 20W50 with added ZDDP anti-wear. Today's off the shelf stuff with designations
SM, SL, or SJ will not suffice for the high stress solid lifters esp. with a hotter cam.
I've got a set of pitted lifters to prove that

[satosh]

Really appreciate the info! Car thankfully came with all manuals, receipts, correspondence and all the original equipment. Six boxes full of stuff. Still digging through it all. I will try n find who did the fuel injection.

In the meantime is this a good oil to use? Lucas Oil 10684 20W-50 Petroleum Oil - 5 Quart Jug, Gray https://www.amazon.com/dp/B009M64D8I/re ... A1K8SR19QW


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[rmel]

Lucas racing/classic is very good, I use it.
There are several good products out there.

[ChickenPinz]

In the meantime is this a good oil to use? Lucas Oil 10684 20W-50 Petroleum Oil - 5 Quart Jug, Gray https://www.amazon.com/dp/B009M64D8I/re ... A1K8SR19QW

There are lots of great oil options out there. I suggest searching the forum for past discussions on this topic to find what works best for your application and preferences.

[MTPinz]

Good looking Pinz!

Do you know if that's factory paint or a respray? It looks super clean regardless.

While you're replacing all the fluids, double check your ignition system too.
Even EFI consumes components such as spark plugs and wires....that'd be one of my first checks to see how balanced the engine is running.

Do you have any exhaust leaks?

As for the long winded oil topic, I've used Valvoline VR-1 20w50 in the past (and present) on vehicles and it is another contender. High zinc levels at a reasonable price. I generally buy in bulk when it's on sale from the local Napa store.

Have fun!

[Fulleraviation]

I would check the valve clearance and ignition timing.

[ChickenPinz]

My thoughts on next steps:
- As everyone else says, change all the fluids so you know where you're starting. Multiple threads on the topic. FWIW, I'm Red-line in my gearboxes and switching to Rotella for the crankcase. No POV on hydraulic fluids yet.
- Check the valve clearances
- Check air filter
- Basically, do all the checks that the Maintenance Manual calls out to set a baseline.

Then...
- Clean every bit of oil off the undercarriage. You want to identify where the leaks are, and you just can't do that well with a greasy belly.
- Consider new tires. Modern tires will drive much nicer than those Maloya ones.
- When you check those spark plugs, take pictures of how they look so you can track issues.
- Lube the cables and the door hinges
- When you change tires, pull brake drums and check the shoes

Here's a link to the MX wall chart: https://drive.google.com/file/d/1CxNYeZ ... sp=sharing

[satosh]

This was great thank you so much. I have done about half the list so far and no issues found. Driven her about 300 miles so far and all good. Is there any tell tale sign a specific fluid needs to be replaced? I have new oil in it and getting a new air filter. Do you happen to know what replacement air filter to use?

Looking into new tires now. It seems the general consensus is 255/85R16 (skinny like current tires and only a few mm more diameter).


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[rmel]

Lots of opinions on Fluid change and inspection -- here's my $0.02 on the subject based on my experience.

First, create a maintenance spreadsheet, having a column for each fluid reservoir. I have 12 columns,
1'st Date, 2'nd Mileage then 10 fluid reservoirs. There's just too many reservoirs to remember when you
did what to whom

Engine Oil: Regularly check your Oil level and replace at 3,000 miles -or- annually which ever comes first.

Wheel Drive: Replace at 6,000 miles. The capacity is rather small, replace frequently.

Differentials: Replace at 8,000 miles. Inspect the "test" port fill level ~4,000 miles . If low top off and note
how much was necessary to add. If you don't see any signs of leaking but oil is being lost, it's either going into
the central tube or into the wheel drives. When draining your wheel drives see if there is more coming out
than went in.

Tranie and X-case: Replace at 8,000-10,000. Inspect level ~4,000 miles.

Hydraulics: Brakes, Clutch, Lockers, Replace every 2 years or immediately if fluid in the reservoir is not clear.

With respect to the air filter, assuming the EFI conversion did not replace the stock filter canister -- Filters
can be bought from Expedition Imports (see above) or Swiss Army Vehicles. You may also find this Parts
Interchange list (Courtesy of Goatwerks.com) useful: http://www.goatwerks.com/interchangelist.htm

I would still like to see a PIX of your EFI conversion and the ECU/controller being used

[satosh]

Thank you. Now to piggy back on this topic I found out that the vehicle has legit only ~3000 miles total, I’d say 1000 were from 2003 to now. ALL fluids were replaced in 2003 ish at ~2000 miles. As such, of the fluids you mentioned which would you consider priority. Stored indoors from 2003-now, started and driven around the block once a week from 2003 onward.

Obv the reason I ask is because even now I’m way under most of those fluid changes.


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[rmel]

Pretty much Fluids hanging for that long all should be considered compromised -- at the very least.

If you need to spread this maintenance out over time, and prioritize....

I'd do Engine first, followed by Tranie, X-case, Portals then Diff's.

As far as the Hydraulics go, if the fluid has been in there that long
the fluid in the reservoirs had plenty of time to absorb moisture.
I'd be worried about the Brakes and Clutch and at the very least
siphon out the old fluid and then bleed the system.

Cheers

[satosh]

Roger that! Really appreciate the info


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[Jim LaGuardia]

Post a picture of your intake manifold and computer.
I’m pretty sure I can identify it with the pictures.
I use EMS computers mounted behind driver seat.

[Texas710]

All great advise. If you do some of this maintenance in stages, visually check your transmission level at a minimum. Sometimes you can develop a small leak that goes unnoticed and that could be very bad.

And remember, most of the time you drain and fill using 2 different plugs (wheels, diffs, transfer etc). Verify you can get both plugs loose (drain and fill) before you totally drain whatever you're working on. It would suck to drain a wheel drive and not be able to refill it properly.

Magnetic drain plugs are a great idea, as well as keeping a good stock of the copper crush washers. Napa is a good source for those.

Nice looking rig btw!