Its Not You Its Me

[Orange Crate]

Here is a conversation I had with Inline Tube (ILT).

ME

Can you describe the differences between these part numbers please. There
is no information on your web site. I know which kits are stainless,
thx, but what are the other details?

CTB71MC42 ,SCTB71MC44, CTB71MC44, SCTB71MC42

ILT

SCTB71MC44 is master to valve lines and the mc42 lines are master to frame lines. It will depend on what setup was originally on the truck. ( did you notice "master to valve" and then "master to frame" which eliminates the prop valve)

ME

MC42 is a kit without lines to go to a proportioning valve? Is that what you are referencing when you say "valve" All four pictures show short lines which go from the master cyl to the prop valve. Do the short lines from the master cyl to the prop valve come in the MC42 kit? (I asked the same question twice)

ILT

Michael, both contain the lines for the same positions and depending on which style is on your vehicle will determine which set you will need. (now we are back to four lines for each kit)

ME

What "style" are you referring to? I put in my information as to make model and year, so what style do I have? 1972 Chevy K20.

ILT

Michael, both styles were used on those vehicles. You will need to look at the pictures for both part numbers and then look at the original lines used on the vehicle to determine which set matches the originals and order those as there is no other way of telling.

ME

Well I still do not know what "style" you are referring to. Line "style", prop valve "style", distribution block "style", master cylinder "style". I have to replace lines I do not have so how would I choose a "style" For a 1972 K20 you have two kits in SS which is right for my truck?

ILT


Michael, both line sets are technically correct for your truck. Those trucks could use either lines depending on what was put on them from the factory. When referring to the style I was meaning of the lines. There is no way for us to determine which of the two sets your truck came with from the factory without seeing the lines.

[Jim Boy]

Hired help??? Try to get in contact with the manager or better still the owner of the company or shop around. Good luck.

[Getter-Done]

Years ago they used to be a Great company to do business with.

I have noticed several people have had issues with them in the past few years.

[my67c20]

I know most are not computer nerds or have fully subscribed to application like Chat GPT or Co-Pilot, but occasionally I find these are good resources to initially understand the differences. Not that I subscribe to the world of useless customer service peeps, but......

Can you describe the differences between these part numbers from Inline tube? CTB71MC42 ,SCTB71MC44, CTB71MC44, SCTB71MC42

Copilot said:
Here’s a clear breakdown of what these four Inline Tube part numbers mean, based entirely on the information available in the official product listings and Inline Tube’s own explanation.

✅ Key Functional Differences
Inline Tube clarified the core difference:

MC44 kits = “Master Cylinder → Proportioning Valve” (master to valve)
MC42 kits = “Master Cylinder → Frame” (master to frame)
67-72chevytrucks
This means the 42‑series and 44‑series are not interchangeable because the routing and line shapes differ depending on whether the truck used a proportional valve setup or a direct‑to‑frame setup.

📦 Part-by-Part Breakdown
1. CTB71MC42 (OE Steel)
Material: OE steel
Function: Master cylinder to frame line kit
Vehicle Fit: 1971–72 Chevy/GMC truck 4WD ½ & ¾ ton
Notes: Designed to replace the short lines that run from the master cylinder toward the frame/ABS module.
inlinetube

2. SCTB71MC42 (Stainless Steel)
Material: Stainless steel
Function: Same geometry as CTB71MC42 → Master cylinder to frame
Notes: Although not listed directly in product pages, Inline Tube’s naming convention uses:
C = OE steel
SC = Stainless steel
Because MC42 = master‑to‑frame, the stainless version (SCTB71MC42) follows the same pattern.
(Functional relationship confirmed by Inline Tube’s explanation.)
67-72chevytrucks

3. CTB71MC44 (OE Steel)
Material: OE steel
Function: Master cylinder to valve (proportioning valve)
Vehicle Fit: 1971–72 Chevy/GMC truck 4WD ¾‑ton
Description: Preformed brake lines from the master cylinder to the valve/ABS module.
inlinetube

4. SCTB71MC44 (Stainless Steel)
Material: Stainless steel
Function: Master cylinder to valve
Vehicle Fit: 1971–72 Chevy/GMC truck 4WD ¾‑ton
This is the stainless counterpart to CTB71MC44.
inlinetube

🔍 Summary Table
Part Number Material Routing Type Meaning
CTB71MC42 OE Steel Master → Frame 42-series = frame routing
inlinetube
+1
SCTB71MC42 Stainless Steel Master → Frame Stainless version of MC42 kit
67-72chevytrucks
CTB71MC44 OE Steel Master → Proportioning Valve 44-series = valve routing
inlinetube
SCTB71MC44 Stainless Steel Master → Proportioning Valve Stainless version of MC44 kit
inlinetube

[pjmoreland]

I wonder if the difference depends on whether your truck has Bendix vs. Delco Moraine master cylinder & combination valve.

[Orange Crate]

I get the feeling that this person does not really know much about ILT or their products. Most replacement lines are CNC bent these days which means they have a CAD/CAM file. Most CAD/CAM files can be printed or output to a CAD drawing. Someone in that company has a CAD drawing for the stock lines, I'll bet.
Also a company that makes replacement parts usually starts with the stock part itself, maybe taking measurements or a digital scan SO when adding any part for sale the stock number can be used as a search term (tag) that allows a person looking for the stock part to be able to find a manufacturer that makes that part or can replace it. For ILT nothing......no stock part number to refer back to, no technical drawing to refer to AND no personnel to be helpful in finding said stock part.....It's Not You It's Me. (classic break up line.....)

[Orange Crate]

Originally Posted by my67c20

I know most are not computer nerds or have fully subscribed to application like Chat GPT or Co-Pilot, but occasionally I find these are good resources to initially understand the differences. Not that I subscribe to the world of useless customer service peeps, but......

Can you describe the differences between these part numbers from Inline tube? CTB71MC42 ,SCTB71MC44, CTB71MC44, SCTB71MC42

Copilot said:
Here’s a clear breakdown of what these four Inline Tube part numbers mean, based entirely on the information available in the official product listings and Inline Tube’s own explanation.

✅ Key Functional Differences
Inline Tube clarified the core difference:

MC44 kits = “Master Cylinder → Proportioning Valve” (master to valve)
MC42 kits = “Master Cylinder → Frame” (master to frame)
67-72chevytrucks
This means the 42‑series and 44‑series are not interchangeable because the routing and line shapes differ depending on whether the truck used a proportional valve setup or a direct‑to‑frame setup.

📦 Part-by-Part Breakdown
1. CTB71MC42 (OE Steel)
Material: OE steel
Function: Master cylinder to frame line kit
Vehicle Fit: 1971–72 Chevy/GMC truck 4WD ½ & ¾ ton
Notes: Designed to replace the short lines that run from the master cylinder toward the frame/ABS module.
inlinetube

2. SCTB71MC42 (Stainless Steel)
Material: Stainless steel
Function: Same geometry as CTB71MC42 → Master cylinder to frame
Notes: Although not listed directly in product pages, Inline Tube’s naming convention uses:
C = OE steel
SC = Stainless steel
Because MC42 = master‑to‑frame, the stainless version (SCTB71MC42) follows the same pattern.
(Functional relationship confirmed by Inline Tube’s explanation.)
67-72chevytrucks

3. CTB71MC44 (OE Steel)
Material: OE steel
Function: Master cylinder to valve (proportioning valve)
Vehicle Fit: 1971–72 Chevy/GMC truck 4WD ¾‑ton
Description: Preformed brake lines from the master cylinder to the valve/ABS module.
inlinetube

4. SCTB71MC44 (Stainless Steel)
Material: Stainless steel
Function: Master cylinder to valve
Vehicle Fit: 1971–72 Chevy/GMC truck 4WD ¾‑ton
This is the stainless counterpart to CTB71MC44.
inlinetube

🔍 Summary Table
Part Number Material Routing Type Meaning
CTB71MC42 OE Steel Master → Frame 42-series = frame routing
inlinetube
+1
SCTB71MC42 Stainless Steel Master → Frame Stainless version of MC42 kit
67-72chevytrucks
CTB71MC44 OE Steel Master → Proportioning Valve 44-series = valve routing
inlinetube
SCTB71MC44 Stainless Steel Master → Proportioning Valve Stainless version of MC44 kit
inlinetube

Most of this is BS. I would not in ten million years use one of those idiot boxes.....

[70STOVEBOLT]

So if I understand this correctly, of all trucks use a prop (combo) valve or a distribution block? How would the pressure be reduced to the rear brakes?? I am not familiar with 20 series or 4WD trucks but I’m pretty sure there has to be some kind of valve/block.

[jumpsoffrock]

Originally Posted by pjmoreland

I wonder if the difference depends on whether your truck has Bendix vs. Delco Moraine master cylinder & combination valve.

I was thinking this same thing.
My '67 Cadillac had the same conundrum.

[Keith Seymore]

Originally Posted by 70STOVEBOLT

So if I understand this correctly, of all trucks use a prop (combo) valve or a distribution block? How would the pressure be reduced to the rear brakes?? I am not familiar with 20 series or 4WD trucks but I’m pretty sure there has to be some kind of valve/block.

A prop valve is not used with a drum/drum system. The proportioning is designed in via the front vs rear wheel cylinder diameters.

Disc/drum will require a prop valve.

K

[70STOVEBOLT]

Keith, I understand the difference between the drum/drum and disc/drum systems, but what truck has neither a prop valve nor a distribution block? If the lines run from the master to the frame, where does the prop/dist block plumb in?

[Orange Crate]

Some good observations here and questions. I would think that a company that makes replacement brake lines would be able to help customers get those replacement brake lines. It seems to me all they do is confuse searches for the correct part. They have one answer and that is "match a crappy picture to what you already have."

[Orange Crate]

Originally Posted by 70STOVEBOLT

Keith, I understand the difference between the drum/drum and disc/drum systems, but what truck has neither a prop valve nor a distribution block? If the lines run from the master to the frame, where does the prop/dist block plumb in?

Mine is a 72 which is the first year for disc front as stock. you input that year information on their site so I would assume that should eliminate the other optional configs, but it doesn't.

[Keith Seymore]

Originally Posted by 70STOVEBOLT

Keith, I understand the difference between the drum/drum and disc/drum systems, but what truck has neither a prop valve nor a distribution block? If the lines run from the master to the frame, where does the prop/dist block plumb in?

Ah - I see.

Yes - every truck is going to require either a distribution block or a prop valve to split the front system M/C line into LF and RF.

Is there a prop valve that mounts on the front frame crossmember, like a squarebody? Perhaps they are making a distinction between there and the valve mounted on the bracket at the Master/booster power head?

K

[Orange Crate]

Yes it is a big mystery what they mean. But they make replacements.....

[MJN]

Originally Posted by Orange Crate

Mine is a 72 which is the first year for disc front as stock. you input that year information on their site so I would assume that should eliminate the other optional configs, but it doesn't.

1971 was the first year for front discs

[pjmoreland]

After spending some time digging around on the Inline Tube website, I suspect one version is for a manual brake setup (no vacuum booster) and the other is for power brakes. They offer those two versions for C20 trucks, and they include "Manual" or "Power" in the descriptions of the two kits. I'm guessing they just failed to include that differentiating description in the K20 kits.

[Orange Crate]

Originally Posted by MJN

1971 was the first year for front discs

71 was optional.

[MJN]

Originally Posted by Orange Crate

71 was optional.

This has been discussed at length on here in another thread- might be worth searching for but regardless, front disc brakes were standard equipment across all light truck models. This screenshot (specifically for K20's) is from the 1971 Vehicle Information Packet and can be viewed here.
https://www.gm.com/content/dam/compa...olet-Truck.pdf

[Keith Seymore]

Since things have quieted down a bit here's my favorite Inline Tube story:

I have a friend named Denny Kloha, who is the original owner of 1967 GTO. He raced the car and twisted the driveshaft and so, disgusted, he let the car sit for many many years.

So - after all these years Denny decided to restore the car. He is super meticulous, as you can tell from the end result. He's also normally pretty soft spoken and reserved.

A couple years ago I was at a show and the Kryta brothers were there with their Inline Tube display. As I walked by John hollered out "hey - Keith - I met someone that says he knew your Dad".

I asked who that might be.

"Some guy, has a 67 GTO, twisted the driveshaft and now he's redoing it" John answered.

"Denny Kloha!" I said confidently.

John then starts telling me about how Denny had called and said Inline Tube gave him a wrong part. The front brake line they sent didn't match the one Denny pulled off the car.

John told Denny that they had used an original owner unrestored car to make the line from and that he was sure it was right. Denny wasn't convinced.

The argument escalated to the point where if they could punch each other out over the phone they would have. They must have agreed to disagree and left it at that.

============

A couple months later I was at the races with my friend Gary Beemer, who is also friends with Denny and his wife Pat.

Over supper that night we were sitting around telling stories, as is our custom, and Gary starts to tell me this same story.

He said he (Gary) and his wife were out to dinner with Denny and his wife when Denny started telling Gary and Carla about this phone call. Denny started getting more and more agitated, and more and more animated, to the point that Gary said other patrons were starting to look over to see what was going on. Gary finally had to get Denny settled down before he had a stroke or heart attack or something.

I thought, at the time, it was pretty funny to hear the same story from two different sources.

===================

A couple months after that I was at the Sloan Summer Fair in Flint, and Denny was there with his GTO. It was probably the first time I had seen him since I was a child and certainly the first time I had seen the car since it was restored.

We had a nice visit, updating each other on how our families were doing when (as you might guess) he started to tell me this same story about his phone conversation with Inline Tube. I couldn't believe it! I let him roll a bit and then finally shared that I had heard it a couple times before.

The only thing I can figure is that maybe Denny's car, built in Pontiac, was misbuilt. It sounds like his front brake line was too long; perhaps the assembler grabbed the wrong line and rather than going back for a different one he simply made it work. I gotta go with Inline Tube on this one.

At any rate, I still think it is hilarious to have heard this same story from three different perspectives.

And Denny now has a perfectly restored '67 Ram Air car with about 10,000 original miles on it.

K

[70 gmc c2500]

Originally Posted by 70STOVEBOLT

Keith, I understand the difference between the drum/drum and disc/drum systems, but what truck has neither a prop valve nor a distribution block? If the lines run from the master to the frame, where does the prop/dist block plumb in?

A drum/drum truck uses a combination valve and while most are located just to the left of the master cylinder some or located on the front crossmember. First year for disc/drum was 71 which uses a proportioning valve and those IIRC are all located to the left of the master cylinder.

As for the part numbers, the numbers starting with an "S" are stainless lines.

[jumpsoffrock]

Originally Posted by Keith Seymore

Since things have quieted down a bit here's my favorite Inline Tube story:

I have a friend named Denny Kloha,

K

Keith, if I ever see this Denny and his high-mileage beater, the first thing ima do is walk directly over to the master cylinder and tell him "you did it wrong"
"you restored the car wrong"
"you ruined it"
"cause its got the wrong brake lines, ya see"
" what wuz the point of wasting all this paint and such a nice rare engine if ya couldn't even get the brake lines right?"














I'd also get a nice shiny Inline Tube sticker and slap it on that "pat-myself-on-the-back" board in the area that says "Thanks to:"

"now these guys know what they're doin, ya shoulda had them do the brakes and this car wouldn't be so bad"

[Keith Seymore]

Originally Posted by jumpsoffrock

Keith, if I ever see this Denny and his high-mileage beater, the first thing ima do is walk directly over to the master cylinder and tell him "you did it wrong"
"you restored the car wrong"
"you ruined it"
"cause its got the wrong brake lines, ya see"
" what wuz the point of wasting all this paint and such a nice rare engine if ya couldn't even get the brake lines right?"

I'd also get a nice shiny Inline Tube sticker and slap it on that "pat-myself-on-the-back" board in the area that says "Thanks to:"

"now these guys know what they're doin, ya shoulda had them do the brakes and this car wouldn't be so bad"

It happens; I came back to my car show spot one time to find a guy sitting in the driver's seat of my GTO.

He said he "wanted to verify the seat felt like it had 4500 miles on it".

[MySons68C20]

Originally Posted by Keith Seymore

It happens; I came back to my car show spot one time to find a guy sitting in the driver's seat of my GTO.

He said he "wanted to verify the seat felt like it had 4500 miles on it".

Oh man I won't even touch someone elses rig unless I have permission let alone sitting in it!