Clutch master problems

JDExSquid

Dodge 2.2TII Swap
Worked on the clutch system all day trying to bleed: no joy. I was using an air powered vacuum bleeder and was getting a little air, but no flow of brake fluid. I was, however, getting a drip in the drivers floor board. To keep it short, a PO had mangled the original flare nut. It was cut off and a compression splice used in its place. Well, 50 percent of the compression splice. The compression "nut" was left off of one side and simply screwed into the master cylinder. Needless to say, it didn't fit. If fluid can get out, air can get in and no bleeding will be taking place today thank you. How in the world am I going to fix this?

On a side note: The brakes bled wonderfully with the vacuum tool at each corner. I have the WHOA brakes on the front, so each caliper has 4 nipples! Still a breeze and I finished all 4 corners the old fashioned way by pumping the pedal and cracking open the bleed nipple.
 
How in the world am I going to fix this?
As long as the female threaded opening on the clutch master hasn’t been mangled, and assuming that you don’t have a bubble flare tool (if you had one, you wouldn’t be asking here, you’d have fixed it already)....

Midwest will sell you a complete clutch hard line with the right fitting and flare (or I may be able to find one in my boneyard). Cut it about 12 inches from the end, so you’ll have a short length that will mate with the master. Get the loaner double flare tool from a FLAPS along with two double flare fittings and a union. Use the flaring tool to flare the cut off end of your short piece. Cut off the bad end of the hard line in the car and flare it, join your short piece in, and you’re good.

Use a double flare for the splice because the fittings are more likely to be in stock at the FLAPS and because they’ll loan you a double flare tool. You could use a compression union instead of flaring (never ever for brakes though - brake pressures are higher and a failure is more dangerous) but flaring is not much more work and makes a way more reliable connection.
 
This clutch master tube nut is non-standard size, M12 x1.25 long style. The original one in the 74' was mangled by the PO. It was replaced by making one on the lathe. Pressures in the clutch system are moderate, but still need to be rated for 1,000 psi. Do NOT use compression fittings in these hydraulic systems as they are not reliable and can fail when least expected.

Do NOT use copper tubing as it will fatigue with pressure cycling and vibration and fail. Copper/Nickel alloy used for brake tubing is good, 3003 aluminum alloy seamless tubing is good (common in small aircraft and home builders), plated/coated steel, or similar will do.

Idea would be to get another M12 tube nut, cut off the original wrecked M12 tube nut then replace it and re-bubble flare the end of this tube. The tube size is 1/4" OD and steel. Using a flare union is also OK, ideally the flare type should be 37 degree single (JIS or AN common in the commercial-industrial-aircraft hydraulic systems) or SAE 45 degree double flare. This 45 degree SAE double flare is far less desirable as it is not designed to be re-used_resealed more than a few cycles where the 37 degree single flare is designed with servicing in mind.


Bernice
 
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I have ordered a used clutch line from MWB. I think I have enough slack in the line to reflare the end, using the nut off of the used line. The line is apparently 6mm, not 1/4". Very close in size but not identical....or so I've been told.
 
Better measure the line with a micrometer or caliper that reads to 0.001"or 0.01mm. Every exxe I've encountered is 1/4" not 6mm.
This was a Federal requirement from that time and why 3/16" OD on brake tubing.

Bernice

I have ordered a used clutch line from MWB. I think I have enough slack in the line to reflare the end, using the nut off of the used line. The line is apparently 6mm, not 1/4". Very close in size but not identical....or so I've been told.
 
I'll warm up my calipers! There is a LOT of tribal knowledge on these cars. Thankfully the WIKI is here to document some.
 
I think I have enough slack in the line to reflare the end,
You will, although it’s a bit of a pain - Fiat didn’t leave you a lot of slack. But do you have a way of making that bubble flare? If you do, you’re good.
 
I have ordered a used clutch line from MWB. I think I have enough slack in the line to reflare the end, using the nut off of the used line. The line is apparently 6mm, not 1/4". Very close in size but not identical....or so I've been told.
Given that we're all metric over here I would think that's possibly right. I've had difficulties in flaring imperial sized replacement pipe while using the original fittings and getting a effective seal. Didn't seem to be enough meat on the flare, possibly due to subtle pipe and/or wall diameter sizes, or fitting sizes, or my incompetence! One way to ease the access issue is to cut the original pipe shorter to a point where you can get access with a flaring tool and then make another short section to go from there to the master cylinder. This short section can be fitted before you install the master cylinder. Obviously you need more pipe and fittings and more chance for leaks, but it it can also make future removal of the master cylinders easier and an accessible point for some basic bleeding of the system if you incorporate a bleed nipple in the fittings.
 
If you can silver solder - one solution would be to make an adaptor line that allows you to move the stock line fitting further back as suggested. I used the female end of a slave flex line to make an adaptor line to go from the Fiat fitting to the Volvo cluthc master, no reason you couldn't do the same to relocate the stock fitting. Maybe it's possible to cut off the banjo fitting from the flex line & add a male barb w/flare that would then screw into the MC? I would think it's possible although I never investigated that approach.

IMG-20200222-160041.jpg
 
Why can't you just use the "new" used line from MWB? Seems a gamble to cut and reflare your old line. So much easier to just swap the whole line.
 
Why can't you just use the "new" used line from MWB? Seems a gamble to cut and reflare your old line. So much easier to just swap the whole line.

Indeed. However, that does involve removing seat, carpeting, probably gas tank (it's routed behind the inner side) etc. I'd cut & flare if it were me :D
 
I would say that depends on your habilities. Changing a line requier patience and removal of many things. To do flares, you need some tools (but its a good reason to buy them) and a knowledge about how-to. Not that is so complicated, but mechanical ability is not equally spreaded...:rolleyes:

25 years ago, I cut my line, redid a flare, bit a union and put a new short line to reach the master. The plus: much easier access to disconnect the master. The minus, one more link, one more place to leak. I was lucky,never had a leak there in 25 years...
 
Indeed. However, that does involve removing seat, carpeting, probably gas tank (it's routed behind the inner side) etc. I'd cut & flare if it were me :D
I was thinking the damaged fitting was on one of the smaller lines located around the master only.
 
Why can't you just use the "new" used line from MWB? Seems a gamble to cut and reflare your old line. So much easier to just swap the whole line.
That works too but it's no less work than just making one cut and two flares. You have to lift the carpet and then feed the line throught a tiny awkward opening behind the fuel tank, and then get the rubber grommet back in.

[Sorry - just saw that I'm late to this part of the discussion]
 
Bernice's offer is great. Bubble flares tend to be a bit more difficult to make than the more common single or double flares typically found on most vehicles in the US. Especially if you haven't done many of them. And even more so when trying to do it under the tight dash confines in that cramped master cylinders area. There are several types of flaring tools that 'can' do a bubble flare, but not all of them are easy to use or even make a good flare. The success of your flare (i.e. it won't leak) will benefit from using a good tool, and we know Bernice has all the best equipment. ;) And there isn't a lot of extra line available to allow two or three tries at it, particularly if yours has already been shortened by a previous owner in a failed attempt to fix it.

That was the thought behind my prior comment about swapping the entire line vs reflaring your existing line. It would avoid the chance of getting a flare that doesn't seal properly and/or not having enough line left for it. But as I stated, I was mistaken about which line we are discussing - thinking it was one of the shorter brake lines. Now that I realize which line it is, I agree the clutch line isn't so easy to swap. But that is an option. Which may present yet another option. You can buy new fittings (correct for this application) from a couple of sources inexpensively. That way rather than cutting the line from MWB to salvage the used fitting, you can add the new fitting to your existing line and reflare it. Then if the flare doesn't seal, or you find the line is too short, you can go to plan "B" and swap the entire line (from MWB). The sources for the correct fittings have been listed in prior threads (we can find the links if needed).
 
Bubble flares are easy to make with the proper tool. The bubble flare is made in a single stroke. The go-to flaring tool is this Facom# 347 but it is a bench only flaring tool.

Double flares are more difficult to make accurately as there are two flaring operations involved and they must hold a degree of alignment for it to seal and function properly. Not a fan of double flare tubing as there is an increased chance of cracked-fractured tubing where the flare end folds over. Keep in mind the 45 degree SAE double flare was invented about 1930 when tubing technology was still developing. Problems with the 45 degree SAE double flare range from that potential to hide cracked flare end fold over, small sealing area, limited re-sealing cycles and ... Yet this inferior tube flare end continues to this day :(

In car, have bubble flaring tools that can work in confined spaces like the clutch tubing in the exxe. That is the flaring tool used to replace the M12 tube nut and bubble flare the cut end of the tube. That would be the loaner tool.


Bernice
 
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