M1008 Brake & Fuel Line Sizes/Length?

[Ackevor]

Checked the TMs and I managed to find one size using GM part number 603827 and its 1/4" brake tubing. There are other brake lines under different part numbers but I just cannot find what size it is.

I'm guessing the truck has sections of 3/16" and 1/4" brake line so I should buy a coil of each?

Fuel line, is it 5/16"?

Finally If I have to get 1 or both sizes of brake line, how long will I need? I figured a 25ft coil of each if I needed both , or 50Ft of one if I only needed 1/4"? I plan to get copper/nickel alloy ($40 per 25 ft 1/4" shipped).

I have spent past few hours trying to find Brake line info so I havn't had time to look up Fuel line stuff so if anyone knows and can save me another few hours it would be awesome.

Thanks!!!

Edit: Cant find size for GM 3696822 which seems to require the most material

 

[the skull]

You will love that cupro-nickel (spelling?) brake line. Cuts and flares like copper.
You can make very nice bends using only your hands. I replaced a couple
of the 3/16 lines on the rear. I would get a coil of 1/4 and a 3/16. For the
fuel line, you could use 5/16 rubber line, that's what I'm going to use.
My good luck. Sorry I can't help on the length, I usually cut to fit.

 

[Ackevor]

Thanks for the info. I just wanted to be sure 25 Ft of each length would suffice to replace all my lines. Am I going to run into a problem where I need 15 different sized fittings or are there only 2-3 different sized fittings throughout? I get the feeling its going to end up being a repair where I removed old, take it with me to buy the new, then go back and repeat unless I can get it all done in a day.

The dilemma Im having now is the bed I just picked up today to replace my current rotted bed still needs a lot of dent repair and some minor rust removal/patchwork. I wanted to find one that only needed repainted but they were all $800 or more and I got this one for $100. The plan was to remove my bed, lift cab a few inches, sandblast everything to clean metal, particularly the frame, and treat/coat/paint everything and install new brake and fuel lines while everything is detached. It will likely take the summer to fix this bed and I don't want to wait that long to restore the frame and other nasty rusted metal, which includes brake lines, only to sandblast new lines to dust haha.

 

[Ackevor]

what size fitting

What flare is on these trucks? Standard or Double Flare?

In the master parts list TM I see a Union fitting. From the rear diagram it shows NSN/Part # 9432075 to the rear of the fitting, and NSN/Part # 137397 to the front, both of which I have no clue what sizes are or if they are the same size.

In short, is union fitting 1/4" both sides?

Trying to buy all the fittings before I tear it apart.

Thanks

 

[cucvrus]

Double flare on all the brake lines and fuel lines that I know of. I even double flare the transmission lines. They seem to hold and match the OEM flares. I never used a single flare on any automotive that I remember. And I would not use rubber fuel line the full length of it's run. That is just me do as you want. But the steel is a little more forgiving and safer in off road use and when something makes contact with it. That is just a suggestion. Do it right the first time spend the time while you are there and do it once and done. Have a nice day.

 

[Ackevor]

Thanks, I planned to do it right the first time and be done with it, truck will be dead before the copper nickel lines give out so I might as well. I just ordered a bunch of 3/16" & 1/4" inverted flare fittings and hope that's all I need on top of 1 union fitting. I think its odd the TM shows 1/4" line with a fitting part number, then use the same fitting part number on the 3/16" line...

Gonna be a few weeks till I get the frame blasted and refinished, hopefully it goes better than when I blasted my new bed

 

[cucvrus]

Yes blasting large areas of sheet metal always ends poorly. That needs a different type of blasting process. Even blasting light truck frames like CUCV's have ends up with poor results. That blasting process removes the rust but also years of useful frame thickness. You can blast a good light frame to pieces if you are not careful. I seen guys get carried away blasting things until they were junk. I seldom get the blaster out. It makes a huge mess and always makes more work on other parts of the truck and sand gets into everything. Short of removing the frame from every part of the truck you will have a lot of clean up work to do when you blast. And you will have sand in places not wanted. Trust me. been there and done all that. I prefer the needle scaler , wire wheels and the grinder. That is my preference. You do it what ever way you have best results.

 

[Ackevor]

Blasting the bed worked out much better than I hoped. I should have clarified I just kept running into problems with the blasting unit haha. First it wouldn't adjust the flow of the media, then when we fixed that the ceramic fitting the hose connects to, got thin & cracked then flew off spraying sand everywhere. Luckily it was pointed in a safe direction and we killed the air supply from the diesel compressor. Then we had a lot of clogging issues because the compressor doesn't have an inline air dryer. A friend is a manager for a major construction contractor and he let me borrow all the equipment free so I figured why not.

As far as the bed though, it turned out great, saved me a ton of sanding time getting it to bare metal, it was covered in layers and layers of paint from spilled cans (came off a paint truck). Got rid of what rust there was and cleared the old undercoating off really well. No warpage or any damage to note.

I will say this, as you mentioned, the media will get into every crack and crevice... which is making me reconsider doing it to my frame with the cab only lifted a few inches... not sure I want sand all over an oil covered engine bay haha. It really only needs redone from the flywheel back, the frame has such a good coating of oil its not rusting hahaha, but further back its rusted bad. Lucky for me though its still solid and no rot anywhere, just needs scaled off and cleaned so I can get a good coat of ZeroRust on it.

 

[Ackevor]

Blew drivers rear brake line off the wheel cylinder today. Luckily I had no load or trailer and was at a gas station about to pull out when I felt pedal get soft. I crimped it off and was about to fill reservoir when I noticed the front and rear are separate.

In the end I drove home just fine with front brakes only and means I need to move up my restoration schedule to get these lines fixed...

 

[Carl1008]

Do you happen to know how many feet of rubber fuel line you ended up using?

 

[Ackevor]

Do you happen to know how many feet of rubber fuel line you ended up using?

No, I left what was on it, a lot of it was actually hard line, only a few joints were rubber at the fuel tank, probably a few more further up but I didn't bother since it all looked fine.

If you wanted to replace it all with rubber line then you would likely need about 15-18 feet. If you plan to reuse hard lines you would only need about 3 feet I think.

 

[Kaiser67M715]

FYI, if you go copper-nickel, 25 ft of each 3/16 and 1/4 is more then enough(I wager it would be close to 2 full trucks with a little left over) but this is how the lines should be, 1/4 from master straight back to rear axle(there is a union somewhere under the rear of the cab-to help when trying to feed the line in, easier in two pieces), where it goes to a soft line to axle, then 3/16 to each wheel, it is 3/16 from master to a "t" to go to front brakes(no 1/4" on front brakes) if you still have the proportioning valve(if CUCV's came with??)(not load valve found in rear over axle), you need a couple extra fittings that are odd size, otherwise most fittings will be the same except for the ones on the master.

measure twice, cut once, leave a little extra for the flare(3/4" should be fine if your pretty good at getting consistent flares), I screwed up when I just did my 1/2 ton GMC, got one side too long, and the other a little short(rear axle, both side should have been same length, but when I got one side too short I added too much and made it too long for the other side)

 

[richingalveston]

I am in need of brake line repair since I just put a screw through the line to the rear. I was considering changing the proportioning valve on the front cross member but not sure it is needed. Mine looks like crap but as far as I know it works.
I did the rear brake disc conversion and I could use a little more brake power. I am considering changing the proportioning valve to an adjustable. and considering upgrading the master cylinder.

From what I understand there is another master cylinder that has larger rear plunger and tank. I am still trying to confirm this.

Some brake lines are needed and where did you source your copper nickel line from and what type of bender and flare tools did you use. I have a cheap flare kit but not sure it has the right sizes. If there are better tools out there I want to know.

thanks.
Rich

 

[Ackevor]

FYI, if you go copper-nickel, 25 ft of each 3/16 and 1/4 is more then enough(I wager it would be close to 2 full trucks with a little left over) but this is how the lines should be, 1/4 from master straight back to rear axle(there is a union somewhere under the rear of the cab-to help when trying to feed the line in, easier in two pieces), where it goes to a soft line to axle, then 3/16 to each wheel, it is 3/16 from master to a "t" to go to front brakes(no 1/4" on front brakes) if you still have the proportioning valve(if CUCV's came with??)(not load valve found in rear over axle), you need a couple extra fittings that are odd size, otherwise most fittings will be the same except for the ones on the master.

measure twice, cut once, leave a little extra for the flare(3/4" should be fine if your pretty good at getting consistent flares), I screwed up when I just did my 1/2 ton GMC, got one side too long, and the other a little short(rear axle, both side should have been same length, but when I got one side too short I added too much and made it too long for the other side)

Yeah I finished the brake and frame job late last summer. I have a bit leftover but messed up a couple sections being my first time so the extra was nice. Thanks for the info, should help others.

I am in need of brake line repair since I just put a screw through the line to the rear. I was considering changing the proportioning valve on the front cross member but not sure it is needed. Mine looks like crap but as far as I know it works.
I did the rear brake disc conversion and I could use a little more brake power. I am considering changing the proportioning valve to an adjustable. and considering upgrading the master cylinder.

From what I understand there is another master cylinder that has larger rear plunger and tank. I am still trying to confirm this.

Some brake lines are needed and where did you source your copper nickel line from and what type of bender and flare tools did you use. I have a cheap flare kit but not sure it has the right sizes. If there are better tools out there I want to know.

thanks.
Rich

Couldn't help you with the master cylinder stuff and disks on the rear. I re-did all my bearings, seals, new drums, shoes, hardware... the works and everything is working good as far as brakes go.

I got everything on amazon. I will leave links below. I do remember one fitting being special at the proportioning valve. It used 3/16" line but had 1/4" sized threads (3/16" line hole with I believe 7/16"-24 threads). I ended up getting a 4 pack of these fittings at Advance Auto I believe.

If you Amazon search "Copper brake line" A list of a few new things come up that would have been handy for me. I bought my fittings separate. There are listing with everything together. This one in particular has both sizes with fittings which would have been nice at the time I bought mine. https://www.amazon.com/Complete-Cop...=1466506542&sr=8-8&keywords=Copper+brake+line

-3/16" Brake line- https://www.amazon.com/Roll-Copper-...=1466506542&sr=8-1&keywords=Copper+brake+line
-1/4" Brake Line- https://www.amazon.com/AGS-CNC425-B...507122&sr=8-2&keywords=1/4"+Copper+brake+line
-1/4" Flare Union you really should need one- https://www.amazon.com/gp/product/B006HI562G/ref=oh_aui_detailpage_o01_s00?ie=UTF8&psc=1
-3/16" Flare nut (3/8"-24)- https://www.amazon.com/gp/product/B006HHRJFY/ref=oh_aui_detailpage_o01_s00?ie=UTF8&psc=1
-1/4" Flare nut (-7/16"-24) https://www.amazon.com/gp/product/B006HHT182/ref=oh_aui_detailpage_o01_s00?ie=UTF8&psc=1
-3/16" rubber line clamp- https://www.amazon.com/gp/product/B003BZQ7EE/ref=oh_aui_detailpage_o02_s00?ie=UTF8&psc=1
-1/4" rubber ling clamp- https://www.amazon.com/gp/product/B003BZQ7H6/ref=oh_aui_detailpage_o02_s00?ie=UTF8&psc=1

The cutter I used- https://www.amazon.com/gp/product/B0050SGPEC/ref=oh_aui_detailpage_o02_s00?ie=UTF8&psc=1 Works great in small spaces

 

[Ackevor]

Forgot to mention I used the a Harbor Freight flare tool. Not the best but with the copper it was so easy to flare and form everything worked fine. I cut a small section of each and kept practicing until I was happy with the flares. Even if its not perfect the flared nuts can kind of shape it when you tighten. I had a couple light seepages but it was expected because I did not want to over-tighten anything. I checked for leaks for about 30 minutes after I would press the pedal, wipe clean and dry all the fitting and tighten any that got wet. Eventually nothing leaked.