Improving reliability

[sigepkat]

I'm supposed to daily drive my '75, but of late, it's been one issue after another...At this point, I've got a 3g alternator, hydroboost, disc brakes, 4 turn steering box, EFI, and a custom dash w/readable gauges. It's also on a 4.5" lift, 35" tires, 3.50 gears, C4 trans, D20 transfer case (w/twin sticks), and a 302. Now, I know that the offroad end of things (lift, big tires, etc) kills the street manners, but what can I do to improve the overall reliability? I'm leaning towards a new wiring harness, since that'll chase down any electrical gremlins I've got, but I wanted to get the groups opinion. What would you do at this point to improve the reliability? Is there something I'm not thinking of?

BTW, for a harness, I'm leaning towards a Speedway harness. A hot rodder buddy of mine did one in his last car and really liked it. I've got the experience to handle whatever is needed for installing the harness (I think.) I spent the better part of my youth installing car stereos, alarms, etc. in all sorts of vehicles...

Thanks for any input!
CM

 

[pcf_mark]

You hit the big items on the reliability list already. Wiring is a question - if yours is good and uncut I would keep on using it. My EFI and transmission controller are on their own dedicated circuits so they are not influenced by the old Bronco wiring. The Bronco wiring is really simple and not failure prone. With your mods you have already fortified it / altered it so you will be doing the same with a new harness.

The other thing you did not mention was your cooling system - are your radiator and hoses up to the use of daily driving? Mine has all new parts but the serp belt chewed through the radiator hoses because they were making contact under certain conditions.

 

[AZOffRoader]

If mine was a daily driver, fuel, ignition and electrical would be the basics and bulletproof. I would replace all wiring if available.

 

[Rustytruck]

If it were mine I would change the axle gearing and get the engine running in its torque band. That would help if your having cooling issues.

Then I would be changing the hoses to silicone hoses so you don't have to change them every other year. When was your C-4 last rebuilt if over 10 years its time to have it gone through. Added transmission cooler? New Motorcraft ignition switch, solenoid and upgraded starter will go along way to keeping you up and going. A stock Bronco is so reliable but once you start the modernization path things start getting complicated and you get more failure points to let you down.

Replacing the system as a unit will keep you reliable. Need brake work replace the pads and shoes and the 40 year old hoses and wheel cylinders brake springs, turn the drums and rotors as a complete project and now the system is in good shape for the next 15 years or so with just pad and shoe replacements.

Check, clean all ground connections. Main one, battery to engine block. battery to steel tub. Battery to frame and I like engine head to firewall. With updated alternator, separate alternator case to ground. This the minimum you need. You will need more grounds if you upgrade to fuel injection. computer likes its own good clean ground.

Old rubber hoses and belts, change them out at the same time with top end stuff and you get a long lifetime of use before you start seeing failures. Cheep shit hoses and belts gets you to start replacing them in 2 years and every year there is something else wrong.
Buy new water pumps, brake master cylinder alternator and starters instead of cheep rebuilt's will go along way for long term reliability.

Replace all your vacuum lines at one time and get rid of any vacuum caps that are covering unused vacuum ports. Plug the unused vacuum ports permanently. soldering a fitting or plugging with epoxy putty will keep things running smoothly.

You don't have to do this all at once but once you start an attack do it right and re-evaluate the whole system with your reliability goal.

Still running the stock driveshaft got a bad u-joint replace them all if their 40 years old.

Bronco still running the old rear axle bearings over 100,000 miles time to replace them to avoid catastrophic failure.

Don't wait for a 5 year old battery to fail change it out just before the battery reaches 5 years. in-depth maintenance will keep you getting to your destination every day and off the hook.

 

[Apogee]

X2...gearing would certainly help out the C4 trans...a cooler should be considered mandatory if you're going to run 3.50's with 35's, but would be good to have regardless.

 

[JAFO]

With mine I rebuilt everything (and I mean everything) and I kept it mostly all stock other than a 2.5" suspension lift, the carb and some cosmetic items that are not period correct for my year. Installed new wiring harness during the build. Haven't had a hiccup in 12k miles since the build completed in 2015. The way it rolled off the assembly line worked just fine.
If you aren't doing a complete rebuild you'll probably chase gremlins off and on with a truck that old. I would think a new wiring harness would get rid of a lot of those gremlins.

Note on my old wiring harness. You can be fooled by wires. The outer coating might look fine. Inside the wire can be corroded and actually acting somewhat like a resistor. Or ready to break. Connectors get old an brittle. And contacts corrode. New harness has new connectors and you can use some dielectric grease on those connections to help seal out water and prevent corrosion.

 

[sigepkat]

To the new gears suggestions...I've actually got 4.10s in the shop waiting for installation, just a matter of finding the time and money to get it done...

I like what I'm hearing, keep'em coming!

 

[Mtgrizzlymn]

Drive mine everyday! Stock point and 4 bbl carb. Hasn't quit yet


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[blubuckaroo]

It sounds like you already have the main points covered.
How about air conditioning? It can't really be reliable if you can't use it year round.

 

[JAFO]

It sounds like you already have the main points covered.
How about air conditioning? It can't really be reliable if you can't use it year round.

Roll down windows is the A/C back in the 70's. I remember the days when A/C was a luxury item and not many cars had it. We survived fine driving them all year round. Typically just a couple of months in VA were it is miserable.

I put factory A/C in my FJ40 and regret doing it. I have used it twice and only because the wife was complaining. I like driving around with the windows down, vents open.

 

[hyghlndr]

I have done the Speedway kit in a replica car, it was of good quality and pretty straight forward. The things to double check are column connections (GM vs Ford style setup), horn, alternator, headlight switch, and keyed starter switch. Just double check these to make sure you wire to the Ford setup.

 

[Broncobowsher]

Keep in mind that when someone has a problem, one of the first things asked is "what have you messed with recently"? Just because parts are new does not mean they are good. The installation of a good part done slightly wrong can cause problems that greatly exceed the potential problems of the part that was already there and working.

 

[broncnaz]

Kinda sounds like you've got the mechanical side more or less covered. Wiring would be a good idea if that's where your issues are. Otherwise like any vehicle things do happen now and then theres no real way to prevent other than regular maintenance and inspection to catch the little things that may turn into issues. Even then stuff still happens just less chance of it if you maintain it.
4.10 gearing will help keep the tranny alive longer than the 3.50 gearing will. They are still considered to be on the high side for 35in tires. But should work fine for street. Offroad Id want something a little lower for less strain on the tranny.

 

[edmedlin]

I put in the Vintage Air system made especially for the early Bronco. It included the ducting and everything, even replacing the old heater motor and the defrost ducts. It works great and does not take as much away from the motor as the old units did. Cooling is something I am working on now. Even with the short water pump, there is not much room between the pulleys and the radiator. I am finding it very hard to do an electric fan setup. I have one in it now, but the front of the water pump is rubbing the fan enclosure. I will probably end up going back to the mechanical fan if I can't work something else out.

 

[Steve83]

...of late, it's been one issue after another...what can I do to improve the overall reliability?

Since you didn't tell us exactly what's UNreliable on the truck, there's no way for us to give you useful information.

...a new wiring harness, since that'll chase down any electrical gremlins I've got...

Not necessarily. New parts aren't always GOOD parts, and even the best wiring harness can be built with honest mistakes. The same goes for its installation. If you can't chase down & repair the faults in the current harness, you probably won't have any better results with a different harness. It'll probably be worse.

Is there something I'm not thinking of?

You didn't list any reliability upgrades you've already thought of %), so again: we can't really answer that question.

Your 3.50 gears seem a little high for 35" tires, but considering the non-OD trans, they're probably about right for a DD. Swapping to 4.10s would make it crawl better, but they won't help its road manners, MPG, or reliability in any way.

 

[Broncobowsher]

.. Swapping to 4.10s would make it crawl better, but they won't help its road manners, MPG, or reliability in any way.

Wrong.
3.50 gears with 35s and a C4 is not going to be reliable. You are against the convertor too much, making too much heat, cooking the transmission to death. All that waste heat comes from burning fuel. Road manors will suck as you are always driving against the convertor.

A set of 4.10 gears will take a lot of the stress off of the transmission, making it last longer and be more reliable. Under most driving situations will probably get you better mileage. And make it more drivable overall.

About the only place the 3.50 gears might be better is highway cruising on pool table flat ground. Even then I doubt it on 35s.

 

[Skiddy]

About the only place the 3.50 gears might be better is highway cruising on pool table flat ground. Even then I doubt it on 35s.

that would be without any wind too

 

[Steve83]

...driving against the convertor.

Could you explain what you mean by that, technically?

Here's a cutaway you can refer to:

#1

It's a lockup-type, but I don't have a Ford cutaway of an older one to use. These are just random ones Google found: (IDK if they're applicable.)

#2

#3

#4

#5

#6

#7

#8

That last one seems to contradict what I presume you mean, but that's why I'm hoping you'll clarify. The page those last 2 came from appears to have been translated from German, and the original source seems to be a Toyota manual. But it seems generic enough to be applicable to this discussion. Here's that link:
http://www.econ-lock.com/index-Dateien/Page885.htm