GTM #534 Build Log

[crash]

I suspect that is the MC you are using for the front brakes.
On my, and all the pictures I can find of others, the front port is for a "bleeder" and the top port is run to the calipers.

The front mc has the line coming out of the top port, going to a tee, and then to each front caliper.

I have discussed this quite a few times on the forums. The bleeder on the high port is the CORRECT way to have the bleeder setup. If the bleeder is not the high point, then how is air expected to leave the system without pumping it all the way through to the calipers? At that point there would be no need to even have a bleeder at the MC. Many, if not most, GTM builders do this incorrectly because it is hard to get the lines to fit because of the frame interference. I would try using low profile banjo fittings.

As far as which master to run to which set of calipers, it should not matter unless you are running staggered size calipers, and/or staggered sized MCs. The only other reason would be if you run a bias adjuster, in which case you would want the "Front" and "Rear" on the adjuster to correlate to the MCs. We run this adjuster on the race car and the center MC is for the front calipers.

[ohmygosuness]

I suspect that is the MC you are using for the front brakes.
On my, and all the pictures I can find of others, the front port is for a "bleeder" and the top port is run to the calipers.

The front mc has the line coming out of the top port, going to a tee, and then to each front caliper.

Thanks, Doug, for the input.

[ohmygosuness]

I have discussed this quite a few times on the forums. The bleeder on the high port is the CORRECT way to have the bleeder setup. If the bleeder is not the high point, then how is air expected to leave the system without pumping it all the way through to the calipers? At that point there would be no need to even have a bleeder at the MC. Many, if not most, GTM builders do this incorrectly because it is hard to get the lines to fit because of the frame interference. I would try using low profile banjo fittings.

As far as which master to run to which set of calipers, it should not matter unless you are running staggered size calipers, and/or staggered sized MCs. The only other reason would be if you run a bias adjuster, in which case you would want the "Front" and "Rear" on the adjuster to correlate to the MCs. We run this adjuster on the race car and the center MC is for the front calipers.

Crash, I believe you're right. The top port is the bleeder, at least according to the user manual. Either way it doesn't look like I can get the lines to fit on the inner-most MC, at least without a fitting that's 90 degrees or low profile.

[crash]

Crash, I believe you're right. The top port is the bleeder, at least according to the user manual. Either way it doesn't look like I can get the lines to fit on the inner-most MC, at least without a fitting that's 90 degrees or low profile.

Again, the banjo fittings are your friend here.

https://www.anplumbing.com/a-n-male-banjo.html

EDIT: Looking at the picture and the adapter you are using it looks like the MC is either an internal flair or the housing uses pipe thread. This may present an issue as the banjo fittings use straight threads. Let me look at some options tonight and I will get back. Could always drill out and retap, but then you would have to disassemble the MC. Have you tried a low profile tube nut and just bending the tube? Our MCs on the race car have moved a bit but I know I have seen others do this on a stock GTM where they make the lower hole work. Banjo is the tightest 90 you will get, it's just going to be a matter of getting it threaded in the MC.

[ohmygosuness]

Again, the banjo fittings are your friend here.

https://www.anplumbing.com/a-n-male-banjo.html

EDIT: Looking at the picture and the adapter you are using it looks like the MC is either an internal flair or the housing uses pipe thread. This may present an issue as the banjo fittings use straight threads. Let me look at some options tonight and I will get back. Could always drill out and retap, but then you would have to disassemble the MC. Have you tried a low profile tube nut and just bending the tube? Our MCs on the race car have moved a bit but I know I have seen others do this on a stock GTM where they make the lower hole work. Banjo is the tightest 90 you will get, it's just going to be a matter of getting it threaded in the MC.

I took some more pictures. It does appear that the threads are straight in the MC. Also, the fittings Wilwood provided also have straight threads.

From the pics, the front may look like a tight fit, but I believe the banjo fittings you linked would go in. The only thing I'm afraid of is that the bolt going through the banjo bore may interfere with the frame.

It's interesting that you mentioned using just a tube with a nut. I used a 20" tube from FFR to test it out and it seemed like it would work nicely. I just need to get a shorter tube so I can T it off.

mc2.jpg
mc3.jpg
mc4.jpg

[crash]

Thanks for the shot down the thread bore. Unfortunately if it does not have an internal flair, which it looks like it does not, then the direct tube and nut option will not work. I took a picture of what we have, which is all banjos, but am having issues sharing the photo. The good news is that the banjo fitting should just work with no mods on what you have there. Simply use what I linked to, along with the properly sized and threaded banjo bolt and then put the tube and flair nut directly on the flared end of the banjo fitting.

[crash]

Finally got the picture to upload.

Master Cylinder Banjo Resize.jpg

[ohmygosuness]

The banjo fitting looks really solid. BUT, it's still unable to clear the frame.
banjo fitting.jpg
The only thing that I could barely get it to fit was a 90 degree bend fitting. But it doesn't look as reliable as the banjo fitting.

[ohmygosuness]

Actually, I may have the banjo fitting installed the wrong way (in the above pic). Here is what it looks like with banjo installed on the 90 degree fitting. It's just enough to clear the frame. Someone please let me know if this works.
PXL_20230425_031104324.jpg

[beeman]

A GTM build will hone your problem-solving skills, any other car projects you take on will be a piece of cake!

[ohmygosuness]

A GTM build will hone your problem-solving skills, any other car projects you take on will be a piece of cake!

I completely agree. I've learned so much already. The GTM pushed me to become a better man

[crash]

Sorry to send you down a rabbit hole. I'll buy the fittings from you if you like. As you can see, they are what we use.

Now back to the issue. The problem I see with your proposed solution is that I believe the fitting you are using is pipe thread and you have it screwed into straight threads on the MC. I don't believe this will work. I have seen others connect up the proper way so I know it is doable. Too bad none of them have provided any pictures or insight.

Have you spoken with anyone at ANPlumbing.com? One of the reasons I use that vendor is because they have people there that will work with you and get you what you need. Prices are pretty close to Summit and Jegs but their searchability is much better. Maybe a lower profile banjo/bolt will work...maybe not, but it might be worth a phone call to ask what they have available?

Then, of course, there is always frame member modification...if you are willing and able. I seem to remember a small modification was done on the other setups I saw with the tubes coming out the front.

[Shoeless]

I completely agree. I've learned so much already. The GTM pushed me to become a better man

This damn build will definitely humble you LOL. But when you get a portion of the work or a major milestone complete, its very rewarding.

[ohmygosuness]

Sorry to send you down a rabbit hole. I'll buy the fittings from you if you like. As you can see, they are what we use.

Now back to the issue. The problem I see with your proposed solution is that I believe the fitting you are using is pipe thread and you have it screwed into straight threads on the MC. I don't believe this will work. I have seen others connect up the proper way so I know it is doable. Too bad none of them have provided any pictures or insight.

Have you spoken with anyone at ANPlumbing.com? One of the reasons I use that vendor is because they have people there that will work with you and get you what you need. Prices are pretty close to Summit and Jegs but their searchability is much better. Maybe a lower profile banjo/bolt will work...maybe not, but it might be worth a phone call to ask what they have available?

Then, of course, there is always frame member modification...if you are willing and able. I seem to remember a small modification was done on the other setups I saw with the tubes coming out the front.

Crash, I do like the banjo fittings. I could definitely use them for the MC's, you don't have to buy them from me lol.

Here is the link to the elbow fitting I got. It's 3AN female to 3AN male:

Podavelle 3AN Female to 3AN Male Flare 90 Degree Elbow Swivel Fitting Adapter Coupler Aluminum Black https://a.co/d/6IZjW98

Let me know what you think. Also, I'm thinking about getting more banjo fitting for the other MC's. They just seem very reliable.

[crash]

I think I see what you are getting at. You are suggesting using the male flare to bottom on the inside of the MC threaded area. I can't tell from the pictures you sent for sure, but there may be a flared or chamfered area on the hole where the fluid comes out of the MC? You are suggesting seating that -3 straight threaded male flare up against that chamfer and then hoping the 90 degree fitting comes out in a usable position. Then using a single flare hard line with a tube nut in the female side of that 90? I have never seen AN fittings used in this way. I think I would try just using a single flare hard line down in the MC with a proper length tube nut and then that should give you the ability to turn the tube right out of the nut and it should result in a very short setup. If you are going to try a single flare setup, I think this is how I would do it and not with all the AN adapters.

[crash]

I don't know if this has the correct thread, but this fitting looks WAY smaller than what you have on there.

https://www.lethalperformance.com/ti...nt=Catch%20All

I went and looked at the Tilton catalog and this is listed for use in the reservoir side. Thread is 9/16 18, probably too large, but very low profile, made out of steel, so I wouldn't worry about high pressures, but I would change the orings out for copper washers.

https://tiltonracing.com/product-cat...arts/fittings/

[ohmygosuness]

I think I see what you are getting at. You are suggesting using the male flare to bottom on the inside of the MC threaded area. I can't tell from the pictures you sent for sure, but there may be a flared or chamfered area on the hole where the fluid comes out of the MC? You are suggesting seating that -3 straight threaded male flare up against that chamfer and then hoping the 90 degree fitting comes out in a usable position. Then using a single flare hard line with a tube nut in the female side of that 90? I have never seen AN fittings used in this way. I think I would try just using a single flare hard line down in the MC with a proper length tube nut and then that should give you the ability to turn the tube right out of the nut and it should result in a very short setup. If you are going to try a single flare setup, I think this is how I would do it and not with all the AN adapters.

I believe I may go with what you suggested about using a tube instead of the AN fitting. But I think the tube end may need to be bubble flare since the threaded area in the MC has an inverted flare/chamfer. I could be wrong, but I think it would be something like this? https://www.force10brakes.com/home/3...-84-p286498003

[crash]

Yes, that is what I meant by a "single flare". It is referred to as a single flare because when you are making a flare on the end of a tube, it is the first step of a two step process to make an "inverted flare". The "bubble flare" or "single flare" is known to not be able to hold as much pressure or nut tightening force, so the "double flare" or "inverted flare"(same thing) is most commonly used. A single or bubble flare should work though, as long as there is a seat on the MC for the bubble to mate to?

[ohmygosuness]

Did the driver side brakes using banjo fittings. Had to order another 6" brake line for the inner-most MC because the one I ordered came with wrong fittings

PXL_20230506_233803630.jpg

PXL_20230506_233813885.jpg

PXL_20230506_233826558.jpg

[ohmygosuness]

PXL_20230508_004550238.jpg

[crash]

I would not have thought of doing it like that. Cool to see people trying new stuff and sharing.

[ohmygosuness]

I would not have thought of doing it like that. Cool to see people trying new stuff and sharing.

Okay. That kind of makes me nervous now . I would have stacked 2 banjo's (like how you have it) if it wasn't for the MC thread being flared the way it is, where I need to screw the banjo thread into the MC, instead of screwing the banjo bolt into the MC. I just hope there's nothing wrong with this setup. I also like how the banjo is able to redirect the lines downward.

[crash]

What I might be worried about is that I try to avoid having solid elements at 90 degrees to a screwed in element because this gives leverage to allow the screwed in element to be unscrewed. Does that make sense? Just curious...why not use the "bubble flare" like you discussed previously?

[ohmygosuness]

What I might be worried about is that I try to avoid having solid elements at 90 degrees to a screwed in element because this gives leverage to allow the screwed in element to be unscrewed. Does that make sense? Just curious...why not use the "bubble flare" like you discussed previously?

That makes a lot of sense. It's actually one thing I'm worried about while putting this together.

I'm planning on using the bubble flare line on the inner-most MC. Because that's the one interfering with the frame. Other 2 MC (middle and far right) will have a banjo.

I may have to come up with a solution to prevent the T from unscrewing due to vibration or other effects over time...

[Shoeless]

My concern is the banjo may leak requiring you to torque it down more and you can't because you have the bolt going straight down.

When I put my brake lines together all the fitting felt really tight, until I filled them with fluid and tried to bleed the system. I had a few leaks that i had to chase around fittings.

[ohmygosuness]

My concern is the banjo may leak requiring you to torque it down more and you can't because you have the bolt going straight down.

When I put my brake lines together all the fitting felt really tight, until I filled them with fluid and tried to bleed the system. I had a few leaks that i had to chase around fittings.

That does sound very concerning. What did you do to fix the leaks?

[Shoeless]

That does sound very concerning. What did you do to fix the leaks?

I simply torqued down the brake/clutch lines more until the leaks stopped. For lines that simply connected to an end fitting or a straight coupling, it was really no problem, just torque down, but where my T fitting was, it caused a minor issue. I had to tighten the T fitting about 1/4 turn from where I mocked it up and the 90 deg output line had to go along for the ride so to speak. Thankfully I had some give in that particular line with a service loop in the line close by so I was able to re-bend the line as I tightened the fitting.

Just something to think about. Not saying it won't work, but I'd fill the lines and try to blead the lines ASAP (I ended up delaying this for some reason) to see if you have any leaks. That way you can address this now instead of further down the road in your build when you get more stuff installed and in the way.

[ohmygosuness]

I simply torqued down the brake/clutch lines more until the leaks stopped. For lines that simply connected to an end fitting or a straight coupling, it was really no problem, just torque down, but where my T fitting was, it caused a minor issue. I had to tighten the T fitting about 1/4 turn from where I mocked it up and the 90 deg output line had to go along for the ride so to speak. Thankfully I had some give in that particular line with a service loop in the line close by so I was able to re-bend the line as I tightened the fitting.

Just something to think about. Not saying it won't work, but I'd fill the lines and try to blead the lines ASAP (I ended up delaying this for some reason) to see if you have any leaks. That way you can address this now instead of further down the road in your build when you get more stuff installed and in the way.

I just ordered a liter of brake fluid. Going to use it to check for leaks. Good call on doing this early than later

[crash]

Good call on this as I almost ALWAYS have to tighten to stop leaks on newly installed parts. I would rather do this than over tighten at first and damage something, so I snug everything, then pressurize, then tighten until no leaks.

[ohmygosuness]

Good call on this as I almost ALWAYS have to tighten to stop leaks on newly installed parts. I would rather do this than over tighten at first and damage something, so I snug everything, then pressurize, then tighten until no leaks.

That reminded me. I do have an air compressor sitting around. It's not much, only 150 psi, but it's less messy than having oil leak everywhere. Is it possible to do a leak test first with just air?

[Shoeless]

That reminded me. I do have an air compressor sitting around. It's not much, only 150 psi, but it's less messy than having oil leak everywhere. Is it possible to do a leak test first with just air?

Negative, the hydraulic pressure present in brake lines is well over 150 psi. Would be a waste of time.

[crash]

I want to say we are seeing brake pressures of around 800 psi...with spikes to over 1000 psi.

[Shoeless]

I want to say we are seeing brake pressures of around 800 psi...with spikes to over 1000 psi.

I figured it would be in this ballpark, but don't measure it on my setup so no factual numbers to share.

[ohmygosuness]

Making a good-looking bubble flare was probably one of the more difficult things I had to do so far with this build (apart from pulling the engine out the Corvette).
IMG_20230601_212619_01.jpg

A direct line to the MC fits perfect. I just hope my bubble flare pass the leak check.
PXL_20230607_235351102.jpg

[crash]

Yeah making either type of flare sounds simple and looks easy when you see the mass produced tubes sitting on the shelf at the parts store, but, as you said, they are rather difficult to get right. The nice thing about the double flare is that if it is not perfect, as you tighten the nut during assembly it will crush the flare to seal on the fitting. This is not the case with the bubble flare. The single, or bubble, flare must have a really nice sealing surface when you are done making it as there is much less "wiggle room" when seating it. Looks good and I hope it seals properly also. Anything that has to do with brake fluid is on my "least favorite" list when working on cars.

[beeman]

The auto parts store rental tools are junk, and anything that style struggles with steel lines. You might be able to flare copper lines. I finally found a tool that works! Need the chamfer tool too.

https://a.co/d/3Q3IYAj

https://a.co/d/74VoszG

[crash]

Here is the one that I use...

https://www.ebay.com/itm/17573792048...518e188d4d9c60

[ohmygosuness]

I appreciate you guys sharing what you use. Now that I think about it a bit more, I should've invested in a tool that's more expensive (assuming I get what I pay for). Braking is quite important, at least to me, since my life will depend on it.
This is the bubble flare tool I bought. It's inexpensive, but seems to get the job done. Although, it does grab the line a bit hard. Hard enough to leave marks. Hope that won't cause any issues down the road.

https://a.co/d/6UgA5e0

[beeman]

I have only had intermittent success with the style that crash and ohmygosuness posted above, hard to keep the brake line from sliding in the clamping mechanism. I've used vice grips on top of those devices, ground down the flats to allow a tighter clamp on the line. I've always used steel lines which are harder to flare, could probably do fine with softer metals with any flaring tool.

[crash]

I have only had intermittent success with the style that crash and ohmygosuness posted above, hard to keep the brake line from sliding in the clamping mechanism. I've used vice grips on top of those devices, ground down the flats to allow a tighter clamp on the line. I've always used steel lines which are harder to flare, could probably do fine with softer metals with any flaring tool.

If you used the Bluepoint tool I referenced and had an issue with grip, then you didn't tighten the wing nuts enough. This tool WILL leave marks on the steel lines, but the line will not move in the tool if you clamp it into a vise to use. The funny looking wing nuts are designed to be used with the tightening bar so you can get some significant leverage on the nuts without the use of a separate wrench. With the tool clamped in a vise and using the included bar on the wing nuts, it gets very tight. Only issue I have had is breaking the double flare mandrel if the tube is not perfectly flat. Using a file after the tube is clamped in the device to make sure the tube end is at the right height and flat to the bar surface reduces the risk of breaking the insert. I do tend to keep 2-3 extra mandrels in the kit because breakage does happen. Make sure to blow out the line after filing.