brake help please

-
silver fox

silver fox

Well-Known Member
Joined
Sep 24, 2009
Messages
158
Reaction score
4
Location
ottawa canada
I have to replace the mc on the 73 duster I'd like to flush out the break line's of the old fluid
& replace with new fluid what is the best way to do this thank's
 
You could try opening all the bleeder screws and let it gravity bleed the fluid out. Or when you bleed the brakes with the new master you could just keep bleeding them until new clean fluid comes out.
 
Yeah, the easiest way is to bleed, keep adding fluid, and bleed until you feel (or can tell) new fluid is flowing.
 
Suck the fluid from the master first and fill with fresh fluid first. Pump and bleed starting at the right rear first. Gravity method with take forever..
 
Would you add 5 quarts of oil to your engine and then drain the old oil until it comes out clean? I didn't think so. don't be lazy. take the lines off at the wheels and the master . Low pressure air in the lines at the master will empty the lines.

The wheel cylinders in the rear will gravity drain from the threaded hole at the wheel cylinder where the line was removed. It will not drain from the bleeder it is at the top of the cavity.
the fronts if drums do them the same way as the rears. If they are disc just push the caliper piston back all the way.

Drain the master by pumping it until the resevoir is empty with the lines off . Put hoses or open lines on the master to prevent fluid from spraying on the car.

If you are committed to change the fluid do it right.

One thing to remember is that brake fluids are not all the same and should not be mixed. Such as lemonade and milk. Down a shot of each this will empty your system .Watch the lumps come out.

You don't know what fluid was poured in your car before you owned it or how long it was in there.
Don't be cheap and lazy as others do it right.
 
Oldmanmopar said:
Would you add 5 quarts of oil to your engine and then drain the old oil until it comes out clean? I didn't think so. don't be lazy. take the lines off at the wheels and the master . Low pressure air in the lines at the master will empty the lines.

The wheel cylinders in the rear will gravity drain from the threaded hole at the wheel cylinder where the line was removed. It will not drain from the bleeder it is at the top of the cavity.
the fronts if drums do them the same way as the rears. If they are disc just push the caliper piston back all the way.

Drain the master by pumping it until the resevoir is empty with the lines off . Put hoses or open lines on the master to prevent fluid from spraying on the car.

If you are committed to change the fluid do it right.

One thing to remember is that brake fluids are not all the same and should not be mixed. Such as lemonade and milk. Down a shot of each this will empty your system .Watch the lumps come out.

You don't know what fluid was poured in your car before you owned it or how long it was in there.
Don't be cheap and lazy as others do it right.
Click to expand...

Edited - misunderstanding
 
if you start taking lines off, be prepared to start replacing them, cuz on a 40plus year old car they are almost guaranteed to be seized. Trying to open those bleeders will be a challenge by itself. Especially the rears. Heat may be and/or, is invariably, required.
If the system has not been opened for many years, there may be many challenges.
 
the mc is off i'll be replacing with a new mc I have loosened the bleeder's the line's all look good I kinda like the low pressure idea which I was thinking about doing blowing out all the crap that might be in the line's then replacing all new fluid's
 
Personally, I wouldn't use that method...by itself. And here's why; take 6ft of clear plastic 3/16 line. Put one end into a clear quart sealer, and anchor it in there, so it can't blow out.Cover it, but do not seal it.
Into the other end pour a small measured quantity of brake fluid.Say 1.0 ounce.Now raise this end up and see how much of it comes out the other end.Well? how much came out?Hmm. Ok now put some air pressure to it. Now how much came out? Now examine the line. You see all the tiny droplets stuck to the tube? The surface tension of brake fluid makes it stick to the tube pretty good.
So if you really want to get it out, you will need to follow the compressed air, with a chemical wash. And every last molecule of the chemical wash will need to come out as well. Brakleen is the chemical of choice. It evaporates well in open air, cuz it has a really low flashpoint.That's why you have to get it out; so it doesn't reduce the boiling point of the new fluid. So now you will need to blow that out. But how can you know it's all out? You can't.
Furthermore, unless you have an air-dryer on that compressed air system, you will be blowing air with some unknown amount of moisture in it directly into your system. How can you know it all came out the other end? You cannot.
So, what's my point?
The point is this; no matter what method you use, there will be contamination.
For me, I feel the least amount of problems is to just pump new fluid in from the top. Not gravity. Pump it in with the pedal. Do it in the proper order, until it runs clear at each station. Then pump a little more out.
If you depend on gravity, the new fluid will roll on through, passing over those molecules stuck to the side of the tube. Pressure bleeding tends to scour the sides some.
I've never had any come-backs using this method.
 
AJ/FormS said:
just pump new fluid in from the top. Not gravity. Pump it in with the pedal. Do it in the proper order, until it runs clear at each station. Then pump a little more out.
If you depend on gravity, the new fluid will roll on through, passing over those molecules stuck to the side of the tube. Pressure bleeding tends to scour the sides some.
I've never had any come-backs using this method.
Click to expand...

I'm not really certain. But pressure bleeding is how I've always done it. I guess you could use pressure from your MIG/TIG bottle, or nitrogen / CO2
 
70DartMike said:
Your advice was great until you got here. Then you turned into an asshole. Get bent.
Click to expand...

Wow I must have hit a soft spot . Sorry if I offended you. I didn't mean to. Just trying help the OP by guiding him correctly. When it comes to brakes I get right to the point.

I mean we are talking brakes here. Short cuts should never be taken with brakes.

When your car shuts down you call AAA. Who are you calling when it doesn't stop? Your Insurance! claims department. Again I am sorry if what I said bothered you it was not dirrected at you. Steve
 
Depends on the condition. Always smart to get as much of the old rusty fluid out as you can before installing clean fluid. I assume you have inspected the wheels. For drums, fold back the rubber dust covers and look for leaking brake fluid. If so, replace the wheel cylinders. In that case, blow out the tubes. On my A-bodies I have done this in a general brake re-furb, so flushed all tubes w/ ethanol and air. Installed new parts and silicone brake fluid, so might never need to touch it.
 
You must log in or register to reply here.
-

Back
Top