an anyone tell me what size lines should be in a 74 dart with front disks? Having some brake issues and am starting to suspect the brake line kit is not right.
thanks, Ray
thanks, Ray
Steel brake lines
- Thread starter halifaxhops
- Start date
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I thought they were all 3/16, but don't recall seeing any option. I got mine from Inline. What issues are you having?
The car does not seem to want to stop after all the system is all new, calipers, wheel cyl, prop valve all lines etc. 10 rear drums and stock front disks, manual brakes. I just changed over a 8" booster, and the master is a 1" BORE. I have not taken it for a ride yet with the new booster, but the car with the 6 seemed to take forever to stop. I do not want to put the 440 in until all the bugs are worked out. Where in SC PA are ya?
I'm in Red Lion. I have manual and not much experience with old power brake systems, but think they ran same size line. I would suspect that you may still have air in lines... Keith
67Dart273
Well-Known Member
All brake tubes on all these cars are 3/16 but there's a catch...........fittings such as t he original drum warning switch or the later combo prop valve, and the master, have special fittings, which were designed so things could not be hooked up incorrectly
I guess anything could happen.........rust, etc in the system, stuck valve, and there's talk of expanding (plugged) brake hoses
Just exactly what does it do?
No pedal
soft pedal
leaking down pedal
poor stopping performance
Can you determine if front or rear is not working well.........try a skid on dirt, etc?
A booster adds a second layer
Booster could be bad
You might have low vacuum to the booster
Last, when "mis" matching parts, you can create a situation where you just won't get good performance. Smaller rear wheel cylinders teamed with a too large master, for example.
I guess anything could happen.........rust, etc in the system, stuck valve, and there's talk of expanding (plugged) brake hoses
Just exactly what does it do?
No pedal
soft pedal
leaking down pedal
poor stopping performance
Can you determine if front or rear is not working well.........try a skid on dirt, etc?
A booster adds a second layer
Booster could be bad
You might have low vacuum to the booster
Last, when "mis" matching parts, you can create a situation where you just won't get good performance. Smaller rear wheel cylinders teamed with a too large master, for example.
Assuming that the system is free of air and has no mechanical problems it sounds like too large of a m/c bore, or not enough boost, or a combo both.
The usually symptom of this is the comment that the pedal feels great, but the car won't stop.
If everything else checks out I'd try a 15/16" m/c. A little change here can make a huge difference. Even a 7/8" m/c can easily be too much.
I have seen rubber brake hoses develop "flaps" inside. Those can cause a range of problems. How old are the hoses? If they're older or of an unkwn vintage then replace them. Never seen or heard of them having this trouble when new or nearly so.
If the planned 440 is going to have a lumpy cam I'd strongly suggest ditching the vacuum booster and going hydro-boost.
The usually symptom of this is the comment that the pedal feels great, but the car won't stop.
If everything else checks out I'd try a 15/16" m/c. A little change here can make a huge difference. Even a 7/8" m/c can easily be too much.
I have seen rubber brake hoses develop "flaps" inside. Those can cause a range of problems. How old are the hoses? If they're older or of an unkwn vintage then replace them. Never seen or heard of them having this trouble when new or nearly so.
If the planned 440 is going to have a lumpy cam I'd strongly suggest ditching the vacuum booster and going hydro-boost.
All the rubber is new, mild cam. Think It might be 1/8 inch lines. Right now is a stock 6 with 17" of vacuum. Just put the booster on this was with manual brakes. Kinda weird right or is it just me? Found the original master it was also 1" bore.
67Dart273
Well-Known Member
No such thing. All these cars came with 3/16, which is the smallest line that can be flared.
You normally (in any production stuff) will never see flared 1/8.
Is it measured inside or out, just scratching my head here. My lines hane 1/8 -24 fittings. Smaller hole if that makes sense.
Ray
Ray
Did you bench bleed the MC if new? Adjust the rear up properly? Install the calipers properly, with the bleed up? Bleed the system?
Walk us through what you have done, not just what you replaced.
Walk us through what you have done, not just what you replaced.
nm9stheham
Well-Known Member
The 3/16" dimension is the outside diameter.
As above, did you bench bleed the new master cylinder? 1" bore is OK; it might stop a bit harder but it will stop A-OK. Does you new MC have different sized reservoirs for front and rear, with the fronts connected to the larger reservoir?
As above, did you bench bleed the new master cylinder? 1" bore is OK; it might stop a bit harder but it will stop A-OK. Does you new MC have different sized reservoirs for front and rear, with the fronts connected to the larger reservoir?
Brake line is considered to be 'tubing' which is measured by OD unlike pipe which goes by ID
Yes all of the above is correct. pretty sure 3/16 is the outside. Just took it for a illegal ride and it is much better with the booster. love to live in the middle of Centrual PA. Sure beats Long Island where I grew up and the tickets are still on my insurance. Look at the dates on the last page of renewal form and will surprise you! Thanks lot for all the help guys/gals. Ray
Nope like a surgeon, looked for that first.
hellfirechrome
Well-Known Member
Have you used a vacuum pump to bleed the brakes? Also, after rebuild, did you prime the master cyl and air bleed that? Lastly, did you rebuild the master? If so, old MC rubbers or unhoned MC bore can kill the whole system
yes all was done, new master. Going to jack it up today and see what size lines run to the rear.
moe7404
moe7404
generally tubing is measured O.D. tubing can be steel / metal / nylon. hose and black iron pipe is measured I.D. generally black iron pipe on the I.D. will be a little over the call dia.
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