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This applies to both Hummers, so I figured I'd just consolidate it here to avoid confusion.

This started with the silver truck. The left front brake line had some tears in the rubber covering. The right side was ok, but I figured I'd just replace both as a precaution given the mileage. This was supposed to happen before the rock park trip.

Then the orange truck sprung a pinhole leak in its left front brake line on the way back from our canoe trip. There's a spongy rubber isolator where the rubber line is crimped to the short hard line at the caliper. The leak seems to be somewhere in there. This happened close to home, so we limped it back.

Along the way I decided I'd just replace all the rubber hoses, on both trucks. It was only another $30 per truck to do the rears, and I thought it might make a nice selling point on the orange one.

Because I was too busy fucking around with the interior, and the door, and the fuel pump, and overlooking a broken fucking leaf spring, I pushed the brake line job on the silver truck off until the Friday before the rock park outing. While I was working on the fuel tank, I noticed all the brake hard lines were vinyl coated. No rust anywhere. The flare nuts were all really clean too. I didn't think it would be a problem.

Well...the flare nuts broke loose from the hose ends fairly easily. But they didn't break loose from that vinyl coating on the pipe. I got a few turns on it before I realized I was twisting the damn brake line.

I backed it off, but that hard line is compromised now.

That brings us to the next whammy. GM doesn't sell brake lines for this truck. They never have. The official repair procedure is to buy bulk line and fittings and build your own.

To make a long story short, I've got 8 flare nuts per truck. All the front ones are seized to the hard lines. 4 of the 6 in the back of the silver truck are seized. Everything in the back of the orange truck came apart perfectly.

And now I don't know WTF to do. I tried using a heavy duty soldering iron to heat one of the nuts on the orange truck because I didn't want to use an open flame near that vinyl coating. It didn't help. I've been soaking them in PB Blaster daily for several days now.

I don't know how to get these fucking things apart without destroying them. I can get pre made stainless line kits off eBay, but I really don't want to spend the money. I can't buy just the individual parts I need. I have to buy a whole kit.

This wouldn't be so bad if it was just one truck. But it's fucking both of them. I don't know what to do. I've still got this leaf spring thing to deal with too.

I was wrong. There's actually 12 flare nuts per truck. 16 if you count the ones that connect to the ABS pump. There's a little junction block for the rear lines that accounts for an extra 4 nuts.

That is bad news. So at least several hard lines are toast? Can you just shorten those hard lines, reflair and make up longer flex ones to compensate?

if they are good condition id probably just cut them and patch in good sections where needed

So, I had to make new hardline crossover pipes on the EvoX Brembos I had when I was doing all of that brake stuff for Stealth. I bought premade hardlines with a flare nut already on each end. Just had to be bent to shape.

Similar to this Brake Line.

The one I linked is for domestic vehicles and is 72" long.

I also bought this tube bender. It is really easy to do actually, even with the weird angles of the Brembo crossover tube. The hardest part in making brake lines is flaring the end properly so it doesn't leak, but these come with the flare already, just need to be bent. The come in various sizes too, so you can figure out what length you need and go from there. You can also rent a flare tool from Oreilly as well.

You can also do what Ryan said as well. When I was deleting the ABS in the Stealth, I accidently cut the clutch hardline by the master cylinder ( :d oh , but I got this 3/16in Tube Union Compression Fitting and was able to splice it back together. Hasn't leaked at all since I did it.

I thought this through some more while I was trying to fall asleep last night. I can get 16 feet of the GM tubing for $45. The fittings are about $3-4 each. That's really not that bad as long as I only have to replace the front lines. The only part I'm still a little fuzzy on is whether or not I can flare them with the basic $20 HF kit I have. I think I can. If not, the professional flaring kit is around $250. I already have proper bending and cutting tools at least.

If I can't free up the lines in the back of the silver truck though, that's gonna suck. I really, really do not want to replace ~30 feet of perfectly good brake line just because the tube nuts are seized up. I need to see if there's enough slack to shorten them and re-flare them like Steve said.

[quote=""Jeff V.""]I thought this through some more while I was trying to fall asleep last night. I can get 16 feet of the GM tubing for $45. The fittings are about $3-4 each. That's really not that bad as long as I only have to replace the front lines. The only part I'm still a little fuzzy on is whether or not I can flare them with the basic $20 HF kit I have. I think I can. If not, the professional flaring kit is around $250. I already have proper bending and cutting tools at least.

If I can't free up the lines in the back of the silver truck though, that's gonna suck. I really, really do not want to replace ~30 feet of perfectly good brake line just because the tube nuts are seized up. I need to see if there's enough slack to shorten them and re-flare them like Steve said.[/quote]

Even if you have to cut the hardlines back, you can have the flex lines extended. With the Brembo's on the Stealth, I bought the EvoX SS kit from Hans, but it wasn't exactly right for the fronts. I found a local auto parts store (non chain) that made custom SS lines for me with the proper fittings, and the length I wanted. The could do rubber too obviously.

Just need to find out what flare type the H3 brake lines use to see if the one you have is the right one. Oreilly has tools to rent for both of the standard brake line flares (37 degree and bubble flare).

Cut and reflare, cut back to a section where you can and reflare, or if the line isn't actually twisted apart use a real torch on the nut and it might come free off the line.

Yes you'll melt the vinyl coating in that area but it's not a big deal.

Problem is, I already ordered all the hoses from Rock Auto. They're sitting in my garage waiting to go on. I don't think doing custom hoses would matter anyway. The hard lines need to mate up with the brackets on the body. I might be able to shift the brackets around a little in the back, but the front brackets are just holes in the shock tower. They're not going anywhere.

Here's the failed brake line from the orange truck. The crimp is basically gone. The new lines don't have that rubber isolator. I can't even figure out why it's there to begin with.



I got the new one installed by pushing the hard line down into the shock tower and spinning the hose on to it. It was a pain in the ass, but I got it done.

Yea that is line is toast. Never seen one rot away like that.

Have you guys got any thoughts on this kind of flaring tool? I've got the typical $20 one with the clamp and die, but this looks like it would be a lot easier and more accurate.

https://smile.amazon.com/ARES-18013-3-1 ... B07RTG5HTM

Double flaring tool. Looks good.

I've never flared lines, so I can't comment. Maybe try on some spare line with what you got to see how it goes, and then get the tool if needed?

Can you not go all AN fittings on these and make it work?


Coop

No. AN fittings have a different flare than standard car fittings. I'd have to replace all the brake lines I already ordered.

Do not do AN fittings they are not reliable and if you wrecked your vehicle you would be on the hook for installing something not designed for brake lines. Do the double flare. Get some spare line if you like. Its not too hard, but you need to make sure everything is straight so the tool can do its job correctly.

[quote=""DCIV""]Can you not go all AN fittings on these and make it work?


Coop[/quote]

[quote=""Jeff V.""]No. AN fittings have a different flare than standard car fittings. I'd have to replace all the brake lines I already ordered.[/quote]

You can't anyway, because AN line is nowhere near rated for brake line pressure. AN line is typically 1000psi. Here are the brake hose/line requirements straight from the FMVS:

"S5.3.2 Expansion and burst strength. The maximum expansion of a hydraulic brake hose assembly at 1,000 psi, 1,500 psi and 2,900 psi shall not exceed the values specified in Table I (S6.1), except that a brake hose larger than 3⁄16 inch or 5 mm is not subject to the 2,900 psi expansion test requirements. The hydraulic brake hose assembly shall then withstand water pressure of 4,000 psi for 2 minutes without rupture, and then shall not rupture at less than 7,000 psi for a 1⁄8 inch, 3 mm, or smaller diameter hose, or at less than 5,000 psi for a hose with a diameter larger than 1⁄8 inch or 3 mm (S6.2)."

I've made brake lines before. Just never this vinyl coated stuff.

I was looking at the GM procedure, and they call for stripping off the vinyl before you install the flare nuts. So there goes my theory that the vinyl is somehow causing the nuts to seize.

The high end crimp tool is kind of the same theory as the one I posted. It just has multiple dies, and a hydraulic hand pump instead of a manual wrench. I'll probably pick it up the cheap one.

This is an aftermarket version of the GM specified tool kit.

https://www.amazon.com/MASTERCOOL-72475 ... B01NCYKQSN

[quote=""Jeff V.""]I've made brake lines before. Just never this vinyl coated stuff.

I was looking at the GM procedure, and they call for stripping off the vinyl before you install the flare nuts. So there goes my theory that the vinyl is somehow causing the nuts to seize.

The high end crimp tool is kind of the same theory as the one I posted. It just has multiple dies, and a hydraulic hand pump instead of a manual wrench. I'll probably pick it up the cheap one.

This is an aftermarket version of the GM specified tool kit.

https://www.amazon.com/MASTERCOOL-72475 ... B01NCYKQSN[/quote]

Meh the vinyl still may be under the crimped end on a OE brake hose from the supplier. But having to replace them it may not be since it is made from just standard lengths of hose. I would assume the Vinyl is only there to prevent the hard lines from rusting.