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Stubies Subie

how do you flush out brake lines?

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Concerning Ol' KC, my 91 Loyale:

 

I was going to flush out the brake master cylinder, as well as the brake lines but noticed when I went to clean out the master cylinder that there was a fare amount of sludge on the bottom of the bowl, close to 1/32 of an inch or so.

 

Trying to gravity bleed the lines didn’t work at all, and I’m guessing that I’ve got some blockage in there somewhere.

 

With as much sludge as I found, and with new calipers and wheel cylinders going on the car, I decided that it would be in my best interest to replace the master cylinder as well, it looked bad enough that I didn’t want to chance it.

 

So with the master cylinder off the car, the calipers and wheel cylinders off, so all that’s left is just the brake lines and nothing else. What would be a good way to flush them all out?

 

Maybe compressed air? A little paint thinner or lacquer thinner? Some solvent? Or just feed through brake fluid until it’s good and flushed.

My concern is that I have sludge in the brake lines and with all new calipers, master cylinder, and rear wheel cylinders, I want to be sure I can get the brake lines as clean as possible before I reinstall everything.

 

Any suggestions or ideas?

Edited by Stubies Subie

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You just pump pump hold like you are bleeding the brake after replacing a caliper or what not. Have a buddy help you, pump until clear folowing the bleed procedure.

 

You can pump out most of the MC (not all of it, do not suck up air), and wie out the insides with a paper towel, and then add more fluid to continue flushing.

 

If you were really particular, you can take it out and get a more thorough cleaning.

 

But this would requre bleeding the MC, (same with replacing it) which can be tricky, and you have to do it with your finger since there is no bleeder valve. This is unnecessary labor for an already functioning brake system.

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This is unnecessary labor for an already functioning brake system.

 

the brake system was bad, rotted out calipers ect, everything is already off the car, all that's left are the brake lines only, and I don't want to install the new master cylinder or calpers and wheel cylinders and feed the sludge through them that's inside the brake lines, I'd like to get the brake lines cleaned out before I put the new parts back on the car.

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I have a vacuum bleeder that would work great for this. You would need shop air to operate it though (they might make a hand pump version). Connect a hose to one end of the open line and drop it into a bottle of brake fluid - vacuum bleed on the other end until it runs clean. Simple one person operation - cheap and easy.

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MAybe you can blow them out with compressed air. Doing this, you will want open ends on the lines. You will probably want to undo the fittings at teh proportioning valve on the rear of the vehicle.

 

Although, i think that just pumping new fluid through by bleeding will do the job. the important part is removing any moisture from the system.

 

Your idea is viable being that things are apart already.

 

I suppose others will chime in with their recommendations.

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If you have compressed air, that combined with a can of AC system flush will get them squeaky clean. http://www.autozone.com/autozone/accessories/Quest-Clean-and-flush-aerosol/_/N-25p8?itemIdentifier=896840_0_0_

I have also seen people use transmission/oil cooler flush kits as well.

OR you could just spray a bunch of brake cleaner in them and blow them out with air.

 

I used the AC system stuff on my neighbors car because some jackass at a local tire n lube place had put OIL in the brake master cylinder. All the seals had swelled up like balloons. I had to replace the MC and all the rubber hoses, wheel cylinders, and rebuilt both front calipers. Problem was I still needed to get the old fluid out of the lines. The AC system flush dissolves oils, and it worked out pretty darn perfect. Blew it out with compressed air and put it all back together. 2 years later, brakes still work perfect.

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If you have compressed air, that combined with a can of AC system flush will get them squeaky clean. http://www.autozone.com/autozone/accessories/Quest-Clean-and-flush-aerosol/_/N-25p8?itemIdentifier=896840_0_0_

I have also seen people use transmission/oil cooler flush kits as well.

OR you could just spray a bunch of brake cleaner in them and blow them out with air.

 

I like the brake cleaner idea, that stuff desolves anyting and drys fast, I can spray that down through the lines, then blow it out with compressed air ...dang! why didn't I think of that? so simple, but that will do it.

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Motive PRESSURE bleeder!

 

Better to "push" than "suck".

 

WOrks great and one person can do the whole job.

 

I suggest getting the appropriate adapter.

 

Money well spent for situations like this.

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Motive PRESSURE bleeder!

 

Better to "push" than "suck".

 

WOrks great and one person can do the whole job.

 

I suggest getting the appropriate adapter.

 

Money well spent for situations like this.

 

I like that one to, I was just looking at them through ebay and google (amazon) that seems like it would do a goo job of cleaning, thanks for the sugestion, I just might have to pick one up

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i have a motive pressure bleeder and a hand pump vacuum style. if i had the lines off already like you id do brake cleaner and compressed air. the pressure bleeder can only do a max of 30 psi... shop air is 120, plus you'd be using a solvent.

 

yeah, id do the latter instead of spending money on a pressure bleeder. for what its worth, i use the pump the brakes with clear tubing on the lines so i can see when the bubbles are out. works considerably better than a vacuum pump, and a million times cheaper than a pressure bleeder. its only worth it to get one of those bleeders if you bleed brakes alot, and only on the cars you have the adapter to fit.

 

for example, i have one, and only the adapter to fit mazda miata and others that share a similar threaded round reservoir. but, all i work on for the most part is purpose built race miata's and i bleed the brakes once a month or so. useful for me, but ask yourself, how often will you bleed them, and what could you get for the price of one?

 

PS: i got the pcv fittings the other day! thanks :banana:

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