Finally fixed my 07 h2's power steering radiator, pulled it out, and promptly blew a brake line. The line that blew came out of the pump on the bottom frame rail, and goes to the front drivers side wheel. I have searched and searched for the line size for weeks and have come up with nothing. I put my micrometer on it and it's larger than 1/4, but I don't know if it's because of the coating or something else.

I would be very grateful if someone could share their experience with replacing a brake line.

 

sstubes.com has complete brake line kits for H2s. Stainless and coated steel. Reasonable prices and from what I can tell good rep.

I mention this not from experience but as someone that is close to pulling the trigger on a complete kit to replace the rusting lines on my 2003.

Hope it helps.

They also have individual lines if you are spot fixing which it sounds like you are.

 

Do you own a FLARING TOOL SET? Easy to check line size 3/16" or 1/4" with it, yet my 56yro eyes can still see the difference looking at it.
Btw, don't waste money on new tools; there's a kit for that:::>>>>>2002-07 Hummer H2 Front Brake Line Kit Steel-TKT0201OM

 

if you guys are replacing brake lines i encourage you to also check the top of the fuel pump as they both rot out at about the same time.

 

I have a tube flaring kit, that's not hte issue. I just have one bad line and it's the shortest among them at about 5' long. I would hate to spend $150 to get one line. I know 3/8 and 1/4 but it's bigger than that, looks more like 5/16. Problem is no one stocks brake line anymore, so I have to order online, and i'd like to make sure of the size before I do so.

 

The Front Left is 0.25" (1/4") as are all the others except the MC1 & MC2 lines which are 0.3125 (5/16") I think.


The above were SS lines fitted Jan 2020.

It starts with just the one failure, but this is a warning sign, go pre-formed stainless, bite the bullet and change them all including MC1, MC2 lines and flexible hoses. Yes SS is harder work with and "seal" but they look great and will never rot.

bronxteck's advice is sound and dropping the tank gives you the opportunity to inspect and replace the FP, will make fitting the rear lines easier, it may also alleviate lifting the body off it's mounts, assuming the SUT layout is a similar to the SUV.

Others may advise using Copper Nickel and forming/bending your own, these are easier to manipulate into place (no body lift required) however it's all down to cost, time and effort and final finish. I believe someone posted they wished they had bought pre-formed than bending their own. SS are about 350% more expensive than steel, but living in a wet climate with gritted winter roads, coated steel will have a limited life.

Safety-wise, most will agree that brakes are extremely important and one fractured steel line is trying to tell you something.

"Dual-circuit" should mean that if say the front failed, the rear would still operate, well maybe it does with a lot of foot pumping, but in my experience brake failure was still catastrophic.

After replacing my front left with copper-nickel, 18 months later I had 3 failures in 2 days, rear right, rear left then MC1 just split apart. It was always my intention to replace them all, just not in the middle of winter, 32°F stuck on an inaccessible gravel driveway, but hey it's better to be alive. Just wished I done the FP at the same time, a few months later that needed replacing too.

Think there's a YT video on brake lines...

 

Thank you for the information. Very informative. But I need the truck for a haul in 3 weeks and it's a thousand degrees in my shop, so I want to get it done for now, and worry about it getting done properly later. heat and ac coming next year in my shop and it'll be much more pleasant to work in. The truck gets about 500 miles a year and is not a primary vehicle, just need it for a tow job for a short time.

In the winter it sounds like i'm due for a complete refurb of the lines. That'll be fun, but at least it'll be cooler.

 

Indeed you have to get your truck running, so here's a few tips (assuming your 07 is similar)

• Before starting take pictures of the line route for reference. It might be easier to cut the line into smaller segments and cut-off at the ABS Module (ECBM)
• Use good quality open ended line wrenches, don't use regular wrenches and 12-point sockets, the last thing you'll want is to do is remove the ABS Module because a fitting has been rounded-off, they can be difficult to undo even with the right tool. The wrench you'll need is a 1/2" / 9/16" (I believe) normally these are cranked at 15°, however you might need to customize one with slightly different angles (blow torch and vice) The reason is it's hard to get the full 60° movement with the other lines in the way, specifically the FL line. Having the 2nd custom wrench makes undoing and tightening easier, which again is hard due to the access (life will be easier if the trucks on ramps)

• As the FL is the most inaccessible of the 6 lines, it's at the rear RHS of the module, access is confined with limited visibility so a good (telescopic) illuminated mirror can prove most helpful.
• Once the fitting has been removed, carefully clean around the ABS Module to wipe away any brake fluid, make sure no debris falls inside. Use the mirror to inspect so you can see exactly how the fitting will screw-in, also having a clean surface will help when checking for leaks later.
• If your making your own line, before fitting the gland to it line, practice screwing it into the ABS Module (ECBM) to "break it in" so to speak. It needs to wind-in really easily as once the line's attached maneuverability is hard and it must go in perpendicularly, again a cross-threaded fitting will be a nightmare !
• If like mine your brake caliper bleed-screw is badly corroded or rotted, you can use the line-gland itself as a bleed-screw (needs two people) this is what my brake guy did and very successfully I have to say.
• BTW the caliper bleed-screws themselves can be hard to extract, it might be worth investing in a new set (with covers) and replace them as you go.
• The good news is the FL line is one of the easiest to route.

Unlike here, maybe you have a Hummer brake expert locally, it would save a lot of faffing about.....

Good luck!

 

So you want to rush a patch then haul with a truck with compromised brake lines..... i hope you don't hurt yourself or your friends/ family or any one else on the road. god speed.

 

bronxteck we tried, but I surmised only the one line is going to get changed.

Think of it 3.5 tons of metal out of control, the outcome is unimaginable....

The three things that shocked me:

1. The corroded sections that were hidden from view.
2. Lines that literally fell apart when disturbed i.e. on the edge of failing.
3. Most of all the MC1 line looked good externally, but ruptured in half i.e. it must have corroded on the inside

On the enlarged section you can clearly see a hole 1/3rd way along from the left, this appeared whilst looking for the leak, I certainly found it!

What a sorry mess.....



"Safety 1st Cooper"