Question on fitting sizes - brake lines

Reprise

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Found out today that the brake line that sprung a leak is one of the hard lines in the rear. After looking for a direct replacement, it turns out GMs part # listed is a 16ft roll of 1/4" tubing. Looks like I'm going to get to learn how to bend / flare a new line. :woohoo:(yeah, right... lol)

Anyway, I searched our site on this, and this poster mentioned that the fittings appear to be oversized (5/16"):


Can anyone confirm? No one answered the guy's post, and I'd like to get this done in one parts run, if I could.

If anyone wants to offer tips, feel free. I'll get back under the truck after the Bears game & finish the eval of what I'm going to need to replace (depending on the run / exact location of the leak, I may splice a union in, for now.) Thanks!
 

Maverick6587

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Dec 16, 2018
730
Sterling Heights, Michigan
You could order the stainless steel Trailblazer SS brake lines below.
They should fit your 03. Just make sure that your brake lines do not have T off. The rear calipers would each need an independent brake line coming from the master cylinder.

An easy way to tell if you have independent brakes lines going to your calipers is if you have the traction control button on your gear shifter/selector.

 

HARDTRAILZ

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Nov 18, 2011
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I actually think they do not fit the pre-06 ones. You should probably double check but at some point there was a change and the lines are different.
 
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Maverick6587

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Dec 16, 2018
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Sterling Heights, Michigan
I could be wrong. I thought the only change was they switched to using flex lines.
 
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HARDTRAILZ

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Nov 18, 2011
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The lines at the rear axle are changed with the stabilitrak addition in 06 iirc.

I know we have weird fittings and I am not sure they did not change over the life of the platform.

Caliper issue: http://forums.offroadtb.com/viewtopic.php?f=15&t=6601

Rear issue:http://forums.offroadtb.com/viewtopic.php?f=15&t=4928
Yeah, it's the rears, they have an odd fitting size and a through bolt in the fitting for mounting... 1/2 20. On top of that the fitting is also a T to go to the other side on 04 and up.
05 and down 06+ does not have that tee
yes, 05 and up is an easy solution. Early models require a bit of cutting and flaring, but still pretty easy. I will post pics and details after I am done wheeling this weekend. Sorry, but there are priorities.
 
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Reprise

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I appreciate everyone's replies. For clarification, I have a LWB '03. Also, I happened to find *one* vendor on the Bay who is selling a preformed set for my truck (US-made, stainless), and ordered them up.

They'll be here by Friday, and I'll post on my view of their quality and the vendor info, for those who might want a set of their own.
 

littleblazer

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Jul 6, 2014
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The difference on the 06 up is that the abs is a 4 wheel system instead of a 3 wheel... the rear axle is tied to one output from the abs module vs later which has 4. This happened across the GM lineup on vehicles that didn't have stabilitrack. On my 03 escalade the lines are different if it has it vs not having it.

Edit: as far as the sizes, the lines are standard size, the fittings are oversized. I was able to reuse the ones on the escalade so I had no concerns on that. I tried, no one stocks them.:tiphat:
 

Reprise

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Sounds like I better not screw up the existing fittings, then. I may hit you up if I can't xfr them over to the new line (the flare that will be on it worries me)
 

littleblazer

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Jul 6, 2014
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If it comes flared it comes with the fittings too I'd imagine no?
 

Reprise

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That's what I thought, b/c the fittings aren't supposed to come off the line. But you mentioned 'reuse' on the 'Slade, so... :confused:

I just looked at the ad again, and I see fittings on the end, so, assuming it's representative of the item, I should be OK. You probably meant on the other end ('caliper end', although they're connected via a flex hose / banjo on the other side.)
 

littleblazer

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Jul 6, 2014
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That's what I thought, b/c the fittings aren't supposed to come off the line. But you mentioned 'reuse' on the 'Slade, so... :confused:

I just looked at the ad again, and I see fittings on the end, so, assuming it's representative of the item, I should be OK. You probably meant on the other end ('caliper end', although they're connected via a flex hose / banjo on the other side.)
I made my own lines lol. My bad.
 

Reprise

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So I got the new brake line kit delivered today. Looks pretty good so far. Even has little rubber caps on the ends that have to be fished into blind channels, etc. For now, I'm just replacing the one that's leaking -- I see where it rusted, which is right at a 90-degree bend, near the fitting.

On the LWB, the rear 'crossover' line doesn't connect on top of the axle; rather, it's clipped to the frame in front of the axle -- and the fuel tank blocks access to one of the clips. It's also a 1pc line, rather than being joined in the center.

I'm going to see if pulling the rear driver's side fender liner will give me the access, but if not, I may have to loosen / drop the tank. The front bolt / strap is nearby.

Anyone know if I can unbolt the front strap, support the front end of the tank with a jack, and lower it a bit without breaking anything in the evap system? I'd need to drop it maybe 3"-6" on that end, I would guess.
If I need to drop the entire tank front / back, I'll do so, but want to avoid that if I can.

Yes, I know I could just cut the line and fish it out, but I'd like to put the new one in all three of the clips, so as to avoid rattles. Plus, I really doubt I can snake the line above the tank in-place, and then down to the frame connection. So a tank loosening (or drop) is probably how I'll have to go.

I did get the old fittings disconnected, and two of the three 'pinlok' clips pulled out of the frame w/o breaking them. Apparently, these plastic clips are another one of those one-off things unique to the 360s / 370s; no other GM vehicle uses them. (I'll post a pic of one once I get the line out with the clips attached, and figure out how it opens up...lol.)
 

Maverick6587

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Dec 16, 2018
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You should be able to drop it 6 inches with little to no problems. Just make sure you keep checking the tension of the fuel lines in the front of the tank. I removed them before dropping my tank, so I'm not 100% sure you will have to or not. There should be enough slack in them though.

You might also have to unhook that purge canister as well. So, also keep an eye on the evap hoses on the rear of the tank.
 
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Reprise

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Got the line replaced. The rear fender liner gives no additional access - fuel tank has to be lowered.

It goes without saying that the less fuel you have in the tank before starting this, the better. Although if you've got a full tank, and you're doing this due to the brake line, the vehicle can't be safely driven, so prepare to siphon the tank, if needed. Or be very careful. Fuel weighs about the same as water (~ 8lbs / gallon, so if you have the large tank, that's about 185 lbs of gas, if full)

This worked for me... (and a reminder that it's only for LWB - the 360s use a tee on top of the pumpkin to connect two smaller length lines together)

Need:
Safety glasses. Rust is everywhere, and it WILL fall into your eyes (and nostrils, and maybe even your ears & mouth.) Big, honkin' chunks of it.

Tank bolts: 15mm socket, probably a breaker bar or impact gun (I used both). And PB Blaster.
Fuel hoses: 7mm socket or wrench, to undo clamps, flat screwdriver or pick tools to break hose seals.
Bracing, jack stands, or two jacks (to hold the tank in place).

You do NOT need to disconnect the front hoses from the tank, or evacuate the fuel system (although it would be good practice to do so (pull fuel pump relay, depress Schrader valve on driver's side fuel rail to relieve pressure)).

Some time before you start this process, spray the frame crossmember bolts. There are holes in the side of the frame near the bolts; use them to spray the bolts from the inside. Also spray the two bolts holding the tank straps in place (front / rear).

Jack up rear of vehicle and place on stands. Retrieve jack. Lower & remove the spare tire. You don't have to remove the rear wheels, but you'll have more room to work if you do.

Use the 15mm socket to remove the four (4) crossmember bolts. If you live in the rust belt, expect that at least one of the four bolts will break, due to corrosion (and if they don't break, the bolts will be corroded, themselves). Hopefully you don't break both bolts on one side.

Loosen (but do NOT remove) the two tank strap bolts (also 15mm). These will be stuck as well.
Position your jack under the front of the tank and lift it so that it will support the tank (or about 1 inch away, maximum). Now remove the front tank strap bolt. If you don't have a second jack, brace up the front of the tank, and move the jack to the rear of the tank. You probably won't be able to lower the front of the tank until the rear strap is removed. But the most you'll want to lower it is about 1" to 1.5", total. If needed, brace things up, and come back to it later.

Before removing the rear tank strap bolt, this is a good time to disconnect the rubber fuel inlet hose from the metal filler line (much easier than disconnecting at the tank end).

Note that if you want the metal filler line to be able to move, there is a speed nut holding a bracket down on the top of the frame (not visible). Remove the speed nut, and lift up on that end, then pull backward to free the front of the bracket (which uses a tab/slot arrangement.) The metal filler line will now move (note the grounding line that connects to the framing for the spare tire - if you break it due to corrosion, remember to reattach it, as it is a safety feature.)

(BTW... If your metal filler line is corroded, this is probably a good time to put in a replacement)

With the fuel hose disconnected, take a look at the top rear of the tank. You'll see two harnesses / plugs, one on each side. If you can get to them now, go ahead and disconnect them, otherwise, you can come back to them in a minute. You don't need to remove the assembly that the right harness clips to - its bracket is attached to the tank.

(If you decide to siphon the tank (I didn't, but I only had 1/4 tank of fuel), now's the time to do that, through the now-accessible fuel inlet)

Position your jack at the rear of the tank, and lift it into place so that it supports the rear of the tank. Now finish removing the rear tank strap bolt. Keep in mind - as soon as this second bolt is removed, along with the strap, the tank will start coming down! Be prepared.

It's hard to remove the rear strap without removing the driveshaft, but it can be bent backward and left hanging in place. That's what I did. (If you decide to drop the driveshaft, those are 11mm bolts.) I also bent the front strap backward a bit, btw.



At this point, you can either lower the rear of the tank, or brace it up and lower the front. I did lower the front of mine about 1-2 inches, before I lowered the rear.

When lowering the rear, you'll need to lower it at least to the 'seam' on the side of the tank, level with the bottom edge of the frame. It can be lowered more than that, but that's the minimum (that's about 6" or so). Do not lower more than necessary to disconnect the two harness plugs, if they're still in place. The harness that connects to the fuel pressure sensor on the right side has a retainer clip above the top of the tank; I disconnected it, but you might be able to get away with just unplugging the connector & leaving that harness retaining clip as-is.

You'll also need to move the rear of the tank inboard (toward the passenger side) 1-2 inches, to have room to remove the last of three (3) clips holding the brake line in place. The other two are on the passenger side (trace the line from the caliper about 12" upward to see it), and almost directly midpoint of the truck. You can see both of these from the passenger side; the last one is in the 'corner' of that rail, and it's obscured by the tank until it's dropped. You'll need a pick tool or a flat screwdriver to pry the round pin up in the middle; the clip can then be pried from the upper rail. The clip opens from the non-hinged side (it's similar to the one that attaches the front brake hose to the bracket on the front knuckle, but I waited until I had the line out (since I didn't know how to release the lock). Note that the plastic tab that locks the clip does not move easily; I wound up just prying the thing out from the outer end (it doesn't break the tab, and although it loosens up a bit to reuse it, it'll hold the new line in place just fine.)

If you haven't already removed the fittings on the brake lines, now's the time to do so. 15mm wrench (line is best, of course). If the fittings are corroded, you may need a pair of vise grips to get the fitting off, if you round off the nut. My passenger side was fine; the driver's side (where it connects to a 'tee') was the bad side. But I got it off without destroying the tee.

The line...
I used a preformed line from a kit I got on eBay (the ONLY place I could find one for LWB). Here's a link to it:


Note that while you get a 'complete' kit (all lines), it is not cheap - about $170 shipped. While the vendor is in the US, and has an external website, this kit is only available for the LWB through the eBay site - it's not listed on their business site (but the kits for the SWB are, IIRC). Good quality (made in US, on CNC machines), and the fittings are correct (see the post I referenced above for info on them - GM uses oversized fittings, relative to the tubing diameter)

I also had to make the 'last' bend on the driver's side - about two (2) forty-five degree bends, along with bending the end 'up' slightly to reach the tee. But it reached OK. If you don't have a tubing bender, take a deep socket and hold it in place where you want the bend. This will create a smooth enough radius for you. On the passenger side, the line touches the frame - either put in something to keep it from rubbing, or bend the line.

While the kit seems to be adequate, if you know how to make brake lines & have the flaring kit, you may prefer to do this over spending $170 on the kit (and having to make minor bends anyway).

So... whether you buy the preformed kit, or make your own... the way to get the line out & back in is via the passenger side. Note how the line feeds above the trailing link and in back of the exhaust hanger when you pull it out. It needs to go back in the same way. Getting it routed through on the tank side was not terribly difficult.

Fasten the center retaining clip in place, but do NOT 'lock' the two side clips, lest you have to bend the line to fit it properly. The amount that I bent the driver's side line meant that I couldn't lock that side's clip back in place - but it's sturdy and doesn't rub against anything.

Screw in the new fittings (I did the passenger side first). Then put the tank back in place & reconnect everything. From there, you're ready to bleed the lines (the rear bleeders are in the front of the caliper and can be seen / reached without taking off the wheels, if you still have them on.

And with that... you're done!
 
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TobyU

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Oct 31, 2019
34
SW Ohio
Let me give everyone some advice for in the future. I have done A LOT of brake lines on vehicles.
It seems like a good idea on paper to buy a preformed line with fitting already on and such but in the reality of installation, it makes it a lot harder. Plus you have the much greater expense on the line cost.

The only time preformed lines are worth it is on a frame off restoration.

Some get a roll of tubing and flare tool but flaring is a pain and scared many away.
The easiest and cheapest overall is to buy the individual straight lines like Rhino Hide in various lengths up to 72 typically.
For most GM cars and smaller trucks, it will be the 3/16 line with metric ends (also called European).
The lines should screw directly into the rubber brake hoses and into wheel cylinders on any drum brakes like a lot of older GM FWD cars.
You will need a bigger fitting for the abs unit inputs and some outputs and also on the little inline check valves that GM used on a lot of vehicles.
This requires either a short adapter line or my preference is an adapter fitting Edelmann 267000 is used often for GM. I just finished a 98 LeSabre and the abs 2 inputs from master cyl were the larger metric 12mm but all four outputs were standard 3/16 line with metric bubble ends which comes on the new lines.
These lines are about 8.00 each and the adapter fittings are less than 4.

You just need to measure what length it will take to get from point A to B and add about 6 inches for error that you can loop or zig-zag to get the end to meet up at the rear connection point.
For runs to rear over 72 inch (60 in some sizes) you use a union but usually called connector for bubble lines(completely different than brass union for standard 3/16 line).
These straight lines are a breeze to run along or through frame rails and over crossmembers and above or alongside gas tanks etc.
You don't have to follow the original route exactly.
You don't have to use the same old brackets as with some cars like ford, that it the first place the lines rust through where the fairly wide plastic hold down bracket touches the lines.
You don't have to remove the old lines or all of them. They won't be doing anything anyway.
If you mess around too much (sometimes even a little) with lines that are routed right next to each other, you will damage the other ones like fuel lines and or vapor return and you will cause or soon have a leak in them too.

I like to hook all the forward part up and tighten it all and while keeping master cyl full or at least some in it and leave the wheel ends open as it will gravity bleed some.
Then I start with right rear and put finger over the end and have someone pump brake as I pop finger off as they push, then cover the end as they let up.
Once you get all fluid (keep master cyl full) you can connect that line and then bleed the wheel cyl or caliper to get last bit of air out.

I did every last inch of brake line on the LeSabre for $65 parts including a qt of brake fluid.

If you try to install a preformed line it is much better to get it on a lift as it makes the contortion act of fishing it where it needs to go a lot easier.
Just last week a guy on the Expedition forum bought a preformed rear one for a 1st gen and upon trying to install asked what his options were for cutting it and hooking the middle back together! That defeats 99% of the intent of buying the preformed line.
What sounds easier is not always the case even if they market it that way.
I still hate doing brake lines and ALL cars should come with factory stainless brake and fuel lines.

I can't believe cars sold in all 50 states are the same (as far as rust protection).
They should have made a "rust belt" package and required it for all shipped to cold states or a "rust durability" package that has stainless lines, Interior coated bottoms of doors and internal rocker protection, extra factory undercoating, and maybe some splash guards.
We have tow packages but not this!

Lincoln Town Cars went to stainless in 1998. I have owned many of them since my first 1989 in 1994. Every single 90-1997 had at least one line rust out and usually more.
Not one 98 and up has had a line leak my oldest is a 98 with 230K on it now.

Brake lines suck and they are a safety issue.
Now if ford would have fixed the rusting away rocker panels on the trucks. GM is at least a little bit better in this area. Of course they didn't even fix the truck or Navigator brake lines in the 2nd gen as they remained steel.

Pinch those pennies but put 10-15K worth of infotainment in new cars.
I'll pass. So I guess I'll keep old ones and keep replacing brake lines. LOL, I can't have all Town Cars.
 

Maverick6587

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Dec 16, 2018
730
Sterling Heights, Michigan
@TobyU Welcome to GMTNation!

Two very extensive posts on brake lines. A lot of great information @Reprise and @TobyU , thank you for your time spent on your writeups!
 
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shadetreejack

Member
Dec 21, 2013
3
Found out today that the brake line that sprung a leak is one of the hard lines in the rear. After looking for a direct replacement, it turns out GMs part # listed is a 16ft roll of 1/4" tubing. Looks like I'm going to get to learn how to bend / flare a new line. :woohoo:(yeah, right... lol)

Anyway, I searched our site on this, and this poster mentioned that the fittings appear to be oversized (5/16"):


Can anyone confirm? No one answered the guy's post, and I'd like to get this done in one parts run, if I could.

If anyone wants to offer tips, feel free. I'll get back under the truck after the Bears game & finish the eval of what I'm going to need to replace (depending on the run / exact location of the leak, I may splice a union in, for now.) Thanks!
Were you able to find a fitting? I damaged one of mine and need a replacement. A 1/2-20 doesn't go past 1-1/2 turns
 

Reprise

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Bear with me, because this was nearly two years ago that I did this repair (it's still holding up well, btw). So I'm reciting this from memory.

I purchased a pre-formed kit, which had new fittings installed. I do seem to remember that it was a little tough to get the one started (due to the bend of the line). So make sure you're 'straight'. Screw it it before running the line, if that helps you ensure that it can be fully inserted / tightened. Also, the receptacles can corrode, so make sure the female end that receives the line is free of corrosion, etc.

And, of course, you want a line wrench for these fittings. I believe the 16mm side of my 16 x 18mm line wrench did the trick, here.

Farther up the thread is a description (by others) of the GM-sized fittings, vs. what's used elsewhere.

Depending on which line you're replacing, I'd go nickel-copper (ni-copp) -- a lot easier to bend than stainless, and if you're replacing the lines that go into the ABS module (driver's side, along the frame rail), you want the softer fitting. Because if you screw up the thread in the receptacle (female) end on the ABS module, that's an expensive (secondary) replacement in itself.
 
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JerryIrons

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Dec 20, 2011
434
I just replaced all 4 brake lines in my ext 06, along with the flexible rubber lines. Fitting size was 1/4" 1/2-20 inverted, kind of a strange oversize fitting
they are not standard, and the napa guy had to look in 3 bins to find them. Bring an old one with you, and maybe something to turn the new one in to make sure they are correct. For my application, that fitting was for both ends, abs pump and also fitting to flexbile brake line.

I think I will write up a small notes post on my experience on this to help others in the future. Anybody who tries to replace brake lines with preformed stuff is just asking for punishment lol.
 
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