Detroit Clatter in the Driveway

Gentlemen,
I present to you my 1979 GMC 7000 with a factory GM Diesel 4-53T (170hp). It has 16,870 original miles on it. It has a Dana Spicer 5250-C 5 speed direct transmission and a 2 speed Eaton rear (5.57/7.60) rated at 18,500lbs. It is gearbound to 58mph, and gets a whopping 10.6mpg's
(850 US miles on 80 gallons of diesel fuel)



I am currently in the process of restoring the truck. The truck did not have working front brakes when I bought it. The front brakes have been replaced, as were every piece on the backing plates. I have duplicated all of the rusted steel brake lines with new nickel copper brake lines. I just need to finish installing them.

You can read more on 4btswaps,
www.4btswaps.com/forum/showthread.php?20...d-GMC-7000-Motorhome

Christopher Kouttron

Nice looking rig Christopher. 10 mpg isn't too bad for something that old. I'm currently holidaying in the US (Texas) but not seeing many old trucks yet.

Not too sure if copper brake lines would pass in Aussie......... I doubt it!

Bruce99 - Copper-Nickel alloy brake tubing is an approved material for braking systems, and has been in use for over 20 years.
It has far superior corrosion resistance to steel, but does not not have the fatigue problems of pure copper tubing.
Typically, the alloy is called 90-10, and it contains 10% nickel, 1.7% iron, 0.8% manganese, and 87.5% copper.

Here's the full story on it .. www.copperinfo.co.uk/alloys/copper-nicke...-ni-brake-tubing.pdf

The tubing is available locally from the following company, if you have brake line corrosion concerns or problems. The brand is Cunifer, and it comes in 25' rolls (7.6M) for $54.95.
It's quite a bit more expensive than steel Bundy tubing, but a low price to pay for peace of mind, particularly with older, single-circuit braking systems, that have no backup.

www.mako.com.au/ibm_custom/search_html/C...ing_x_25_foot_62.htm

Cheers - Ron.

As Ron mentioned, Nickel Copper brake line is actually a good bit superior to steel line, and in many ways comparable if not better than stainless brake line. The Cunifer brake line is as durable as stainless steel, yet easier to flare and bend. I am using a Brakequip BQ-350 professional flaring tool to make the flares (45 degree double flare), and an array of Ridgid tube benders. This truck has 1/4" and 5/16" brake lines, and 3/8" fuel lines which I am all replacing.

The truck is air over hydraulic, and the air leaks it has are quite audible, yet the air gauge remains above 120psi when running. I know there is a small leak somewhere and it will be fixed before she gets on the road. I am not sure how well the air booster is working, as there are a number of cut wires on it, may have been from the previous owner, who removed the 5th wheel to install the camper body, and didn't realize it had air assisted brakes...

I paid $4000 for the truck (mainly because of the low mileage engine), and have $5900 into fixing it so far. I expect another $5-6K in damage before the brakes are 100% new, change of rear gears to make it go a bit faster, redo the floor in the cab, and some of its rotted away supports, redo the seats (keep the air ride for the driver seat, and install a bench with something more than just lap restraints), new dash board with SW gauges, a few mods to the engine, and a nice silver/black paint job.

Chris