Brake master cylinder R&R questions - rounded bolts...
Thread Starter
Melting Slicks
Joined: Jul 2004
Posts: 3,277
Likes: 32
From: Mission Viejo California
Brake master cylinder R&R questions - rounded bolts...
Hi guys. I'm in the process of trying to replace my master cylinder on my 92. The aluminum hard lines are the problem. The front one (the bigger one) came off nice and easy. The rear one is being a pain. The rear one is slightly rounded already.
Before I screw things up, what is the correct size flare wrench for the rear one? I was told an 11 mm but with it being somewhat thrashed already, I can't get a standard 11 mm wrench around it. The 12 will go on but feels just a tad loose.
My next question is, can I replace this fitting? I'd imagine that if this thing gets at all worse, I'm definately going to have to replace it. Can this be done easily or is it going to be a major chore? I don't know much about the aluminum lines, but I'd imagine that you put the piece on there and then flare the aluminum so that it won't slide off and is pushed against the fitting as it's cranked down. Any info on the replacement of this part would be helpful.
The car currently has no brakes, so I can't really drive it anywhere. I'd have to tow it to the shop if it's something that the shop needs to handle. I have the new master cylinder here and ready to go but this fitting is driving me nuts!!!!
Before I screw things up, what is the correct size flare wrench for the rear one? I was told an 11 mm but with it being somewhat thrashed already, I can't get a standard 11 mm wrench around it. The 12 will go on but feels just a tad loose.
My next question is, can I replace this fitting? I'd imagine that if this thing gets at all worse, I'm definately going to have to replace it. Can this be done easily or is it going to be a major chore? I don't know much about the aluminum lines, but I'd imagine that you put the piece on there and then flare the aluminum so that it won't slide off and is pushed against the fitting as it's cranked down. Any info on the replacement of this part would be helpful.
The car currently has no brakes, so I can't really drive it anywhere. I'd have to tow it to the shop if it's something that the shop needs to handle. I have the new master cylinder here and ready to go but this fitting is driving me nuts!!!!
Le Mans Master
Joined: Aug 2003
Posts: 9,884
Likes: 3
From: Magnolia Mississippi
St. Jude '03-'04-'05-'06-'07
yea you can replace, but you'll need a flare tool, fitting and be careful, not alot of line... If it already rounded i'd be careful using any wrench that can round more....
Le Mans Master
Joined: Jan 2002
Posts: 9,036
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From: Edmonton AB
Team Owner
Joined: May 2002
Posts: 24,337
Likes: 25
From: San Diego , CA Double Yellow DirtBags 1985..Z51..6-speed
Flare nut wrenches will be a little loose, but it does grip on 5 sides of the nut.
The threads are 12mm metric, so the hex has to be metric also. 7/16" is inbetween 11mm and 12mm, give that a shot.
If nothing else, get some vice grips on there, preferrably the ones where the jaws wrap around partway, and clamp that sucker on there and twist. It will mangle the fitting, but it will be reusable (with vice grips), and it sure beats putting a new fitting and reflaring the tube, or paying a mescamic to fix it.
The threads are 12mm metric, so the hex has to be metric also. 7/16" is inbetween 11mm and 12mm, give that a shot.
If nothing else, get some vice grips on there, preferrably the ones where the jaws wrap around partway, and clamp that sucker on there and twist. It will mangle the fitting, but it will be reusable (with vice grips), and it sure beats putting a new fitting and reflaring the tube, or paying a mescamic to fix it.
Thread Starter
Melting Slicks
Joined: Jul 2004
Posts: 3,277
Likes: 32
From: Mission Viejo California
damn, this is frustrating....
I tried the 12. It just spins on there. I tried several sets of pliers but this thing is really on there. I already sprayed it with liquid wrench. Man, I could strangle whomever put this tiny fitting on this thing. The 14mm large one came off with a regular wrench even. This sucks.
I tried the 12. It just spins on there. I tried several sets of pliers but this thing is really on there. I already sprayed it with liquid wrench. Man, I could strangle whomever put this tiny fitting on this thing. The 14mm large one came off with a regular wrench even. This sucks.
Thread Starter
Melting Slicks
Joined: Jul 2004
Posts: 3,277
Likes: 32
From: Mission Viejo California
I tried using those. Whomever worked on this car last and over tighted the damn thing.... arrrggg!!!!
I ended up cutting the fitting in half using a cutting wheel. I had that one 70's song that goes "no more mr. nice guy..." playing in my head as I did it.
I got a double flare tool kit from autozone. What size is flare again? It has 4.75 and 5.
Also, I just installed the drm spring in the assembly in my old master. Do I have to remove it from that assembly and reinstall it in the new one or can I just swap the assemblies?
Thanks for the help guys. This would have sucked without reading the threads and getting the advice.
I ended up cutting the fitting in half using a cutting wheel. I had that one 70's song that goes "no more mr. nice guy..." playing in my head as I did it.
I got a double flare tool kit from autozone. What size is flare again? It has 4.75 and 5.
Also, I just installed the drm spring in the assembly in my old master. Do I have to remove it from that assembly and reinstall it in the new one or can I just swap the assemblies?
Thanks for the help guys. This would have sucked without reading the threads and getting the advice.
Le Mans Master
Joined: Jan 2002
Posts: 9,036
Likes: 13
From: Edmonton AB
Your car requires an ISO Flare, aka Bubble Flare as discussed in Performance Nut's
thread - link provided earlier.
You might want to pick up some pre-made brake tubing to practice on before
going 'live'.
Read what PN had to say about using the flaring tool and about bending the
OEM tubing. He had some photos and text but these were later edited.
.
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Advice..be sure the new nut you buy ill even thread into the hole(s).
Sometimes people that worked on the car in the past,cross threaded the old stuff and when you finally get it off,the threads inside for the new nut on the line wont even go in.
Be sure its all good before assuming it was just the nut that was bad on the line.The MC is way stronger but be sure the threads inside are good too.
Sometimes people that worked on the car in the past,cross threaded the old stuff and when you finally get it off,the threads inside for the new nut on the line wont even go in.
Be sure its all good before assuming it was just the nut that was bad on the line.The MC is way stronger but be sure the threads inside are good too.
Le Mans Master
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From: Director of Bands
St. Jude Donor '08
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St. Jude Donor '04-'05-'06-'07
Melting Slicks
Joined: Oct 2004
Posts: 2,510
Likes: 4
From: Austin Texas
I replaced a MC nut a while back using ISO bubble flare tool. I had to order this flare tool kit online as I could not find it at any local auto parts stores.
Here's a writeup I did.....
http://forums.corvetteforum.com/show....php?t=1589717
Here's a writeup I did.....
http://forums.corvetteforum.com/show....php?t=1589717
Le Mans Master
Joined: Jan 2002
Posts: 9,036
Likes: 13
From: Edmonton AB
I replaced a MC nut a while back using ISO bubble flare tool. I had to
order this flare tool kit online as I could not find it at any local auto parts stores.
Here's a writeup I did.....
New Brake booster/MC and ISO bubble flare finished!
.
order this flare tool kit online as I could not find it at any local auto parts stores.
Here's a writeup I did.....
New Brake booster/MC and ISO bubble flare finished!
.
Your posts and pictures will be a great help to people who need to
repair brake line fittings.
.
Le Mans Master
Joined: Jan 2002
Posts: 9,036
Likes: 13
From: Edmonton AB
Some key remarks by MikeC4 in his thread
- Do not forget to put on the new flare nut before you flare your brake line!
.
- Do not forget to put on the new flare nut before you flare your brake line!
- I bought 3 feet of 3/16" brake tube to practice on. I made about 5 practice
Bubble flares until I felt comfortable enough that I could do it correctly
on the real brake line. - When making a flare, it is recommended to put small amount of brake fluid
on the tip of the brake line for a "cleaner" flare. This helps reduce the
friction between the flare fitting and brake line as you are turning the crank! - Best to have 2 people on this job, 1 to hold the flare clamp, and the other to turn the
crank. Bubble flares require much more rotational torque than SAE Double flares.
(And there isn't the luxury of mounting the die or flare clamp in a vise
when working in the engine compartment.) - Do your best to get your flare correct the first time, as there is not
enough straight pipe left to do another flare if you mess up the first.
- Do not forget to put on the new flare nut before you flare your brake line!
.
Thread Starter
Melting Slicks
Joined: Jul 2004
Posts: 3,277
Likes: 32
From: Mission Viejo California
Hey guys. Any suggestions on where to pickup this tool since I got the wrong one? Also, do you know the part number for the smaller fitting on the 1992 brake master that I stripped?
thanks!
thanks!
Team Owner
Joined: May 2002
Posts: 24,337
Likes: 25
From: San Diego , CA Double Yellow DirtBags 1985..Z51..6-speed
There is no part number for it.
You just have to find a piece with the same thread size and tube size.
I go here for that sort of stuff:
www.mcmaster.com
You just have to find a piece with the same thread size and tube size.
I go here for that sort of stuff:
www.mcmaster.com
Melting Slicks
Joined: Oct 2004
Posts: 2,510
Likes: 4
From: Austin Texas
I got mine directly from local auto parts counter.
Mfgr: Edelmann
P/N 121050
size: 10mm X 1.0
Bar code : 21597 50980 3
(The larger one is a 12mm X 1.0, which I got at a GM parts counter, don't have the P/N on this one though)
Mfgr: Edelmann
P/N 121050
size: 10mm X 1.0
Bar code : 21597 50980 3
(The larger one is a 12mm X 1.0, which I got at a GM parts counter, don't have the P/N on this one though)