Brake fluid change

Sixpactogo

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I swapped my front drums out for Disc's many years ago on my 60 Dart. May have used synthetic fluid at the time but don't remember. Recently checked the fluid and added some dot 3. Now my brakes are locking up after a short drive. I suspect the new fluid is not playing nice with the old and swelling up. I plan on purging out the old fluid until I get new clean fluid at each wheel. My question is, will that cure my issue or do I need to flush the system?
 

Sixpactogo

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Probably what I had in there since I do remember using Dot 5 in one of my old cars.
 

thrashingcows

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If you have Dot 5 in your system can you flush the system and run Dot 3, or will all the hoses, calipers and wheel cylinders need to be replaced?
 

Davea Lux

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If you have Dot 5 in your system can you flush the system and run Dot 3, or will all the hoses, calipers and wheel cylinders need to be replaced?
You should replace the brake hoses because it is very difficult to get all the old fluid out of them.. The calipers and wheel cylinders should have new kits installed. As noted DOT 5 does not play well with other fluids.

Dave
 

Sixpactogo

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You should replace the brake hoses because it is very difficult to get all the old fluid out of them.. The calipers and wheel cylinders should have new kits installed. As noted DOT 5 does not play well with other fluids.

Dave
Kinda finding that out. I bled both calipers until I got nice clean fluid and thought I was done. After driving the car about half an hour I noticed the brakes starting to drag. By the time I got home and jacked the car up, the front brakes were tight. Tomorrow it will be new hoses and calipers. The rears seem to be doing OK. Probably will bleed them again just for good measure.
 

CBODY67

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What does the rubber flap/seal on the underside of the master cyl cover look like? If it has grown in size, you might as well get a good master cyl on the car, too. Kit/replace everything that has rubber in it, plus new hoses (as mentioned).
 

Sixpactogo

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What does the rubber flap/seal on the underside of the master cyl cover look like? If it has grown in size, you might as well get a good master cyl on the car, too. Kit/replace everything that has rubber in it, plus new hoses (as mentioned).
Master cyl flap looks good. I gave it a bath with brake cleaner and it has not swelled at all. I am waiting for my new calipers so today I plan on taking the Master off and spray some brake cleaner in the tubes and give em a blast of air before putting it all back together. No more DOT 5 for me. Thanks guys for the tips and help.
 

CBODY67

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Seems like there are two "DOT 5" brake fluids? DOT 5 and DOT5.1? One silicone and the other one synthetic, or something like that? It's been a while since I looked at that stuff.

Just some thoughts,
CBODY67
 

Sixpactogo

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Well, I think the brakes on my Phoenix are back to normal. I removed the Master cylinder, took it apart, cleaned and honed it, replaced the calipers and rear cylinders. Flushed the lines with brake cleaner & new DOT 3 and bled all four wheels. I test drove it about 40 miles today and all seems to be playing by the rules. Just in time too. Heading to Mopars in the Park tomorrow morning.
 
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