brake fluid

[happyjackdaddy54]

I'm just about done with the brake system on my 64 Fury. It has a Mopar master cylinder , Mopar caliper's. I'd like some feedback about what type of brake fluid to use. I know dot 4 has a higher boiling point than dot 3. dot 5 higher than dot 4. What are the benefits of using dot 5? I have all new lines installed. So, contamination is not an issue. Any input guys?

 

[MoparMitch]

I like to use Dot 5 in all my Hot Rods, as it is not hydroscopic, and it doesn't eat paint like Dot3 or 4. Never had an issue using it. I have it in one car now for 25yrs. Now, some will tell you it doesn't have the same boiling point, doesn't stop as well. yada, yada, yada.. But it works well for me.. and doesn't make a mess IF it should leak..

 

[440+6]

I have dot 5 in my gtx for over 20 years, used it to push out the dot 3 after a master cylinder rebuild and never had a problem, stops great.

 

[69L48Z27]

I stick with DOT 3, no real reason why other than to keep all my cars the same. No worries trying to remeber what car has what fluid. DOT 5 is great for restoration and not dealing with paint spilled on.

 

[PRND21]

Dot 5, same reasons as MoparMitch.

 

[Cornpatch MO]

I'm just about done with the brake system on my 64 Fury. It has a Mopar master cylinder , Mopar caliper's. I'd like some feedback about what type of brake fluid to use. I know dot 4 has a higher boiling point than dot 3. dot 5 higher than dot 4. What are the benefits of using dot 5? I have all new lines installed. So, contamination is not an issue. Any input guys?

I have used DOT 5 for several years , with no negative issues. the advantages are many. I am also using it in my just about finished current project. I used to get a lot of flak for using it, but it is now more widely accepted. . Do not let it mix with Dot 3. I would like to find a lable or something , to warn about useing nothing but dot 5 in the master cylinder.............................MO

 

[dvw]

Dot 5 in my stuff since the world was in black and white.
Doug

 

[happyjackdaddy54]

THX guys!

 

[67 GTX]

I switched over to Dot 5 from Dot 3, and the pedal acts weird now. It is extremely stiff when the car isn't moving, but softens up under braking.
The car has manual drum brakes all around.

 

[RJRENTON]

Gentlemen,
I concur whole heartedly ..... FOT 5 silicon fluid is the only way to go in everything except cars with antilock brakes....theyuse only the DOT 3 or 4 fluid.
DOT 5 fluid is non hydroscopic....it does not absorb moisture and moisture is the ruination of braking systems....it causes the wheel cylinder pistons and caliper pistons to corrode and leak. In addition it causes the rubber flex connections to become hard and brittle over time. I replaced all of the brake system components (calipers, hoses, rear wheel cylinders, master cylinder, proportioning valve) on my 70 GTX, RS23VOA***** many years ago (10) following individual failures. I have NOT had any problems of any kind since the total system change over. The only regret is not having done it sooner. Yes, DOT 5 fluid is more expensive (3x more than DOT 3) but to me, cost is not the determining factor....better performance and reliability is. This is just my opinion

 

[67 GTX]

Gentlemen,
I concur whole heartedly ..... FOT 5 silicon fluid is the only way to go in everything except cars with antilock brakes....theyuse only the DOT 3 or 4 fluid.
DOT 5 fluid is non hydroscopic....it does not absorb moisture and moisture is the ruination of braking systems....it causes the wheel cylinder pistons and caliper pistons to corrode and leak. In addition it causes the rubber flex connections to become hard and brittle over time. I replaced all of the brake system components (calipers, hoses, rear wheel cylinders, master cylinder, proportioning valve) on my 70 GTX, RS23VOA***** many years ago (10) following individual failures. I have NOT had any problems of any kind since the total system change over. The only regret is not having done it sooner. Yes, DOT 5 fluid is more expensive (3x more than DOT 3) but to me, cost is not the determining factor....better performance and reliability is. This is just my opinion

Have you noticed any difference in your brake pedal between dot 3 and dot 5?

 

[RJRENTON]

67GTX,
INITIALLY, after first installing DOT 5, fliid and after bleeding the system to insure all air was eliminated, I found ABSOLUTELY NO DIFFERENCE in braking "feel" (what ever that means). 10 years later, there is no corrosion or system degradation and the braking system continues superbly without issue
Bob Renton

 

[67 GTX]

67GTX,
INITIALLY, after first installing DOT 5, fliid and after bleeding the system to insure all air was eliminated, I found ABSOLUTELY NO DIFFERENCE in braking "feel" (what ever that means). 10 years later, there is no corrosion or system degradation and the braking system continues superbly without issue
Bob Renton

Thank you. Perhaps the car needs another bleed.

 

[67 GTX]

After switching from Dot 3 to Dot 5, has anyone gotten an extremely stiff when the car isn't moving, but softens up under braking.
The car has manual drum brakes all around.

 

[AMX364]

YES-now with a good strong flashlight looking inside the master cylinder, remove the mounting bolts and check if the piston moves. The piston pushrod might be too long, if it moved gently make it a little shorter(grind) till the piston does not move.

Leave all lines connected and you should not have to rebleed. This issue has nothing to do with type of fluid and more to do with clearances, also not Mopar specific issue.

 

[67 GTX]

YES-now with a good strong flashlight looking inside the master cylinder, remove the mounting bolts and check if the piston moves. The piston pushrod might be too long, if it moved gently make it a little shorter(grind) till the piston does not move.

Leave all lines connected and you should not have to rebleed. This issue has nothing to do with type of fluid and more to do with clearances, also not Mopar specific issue.

Are you saying to shine a light into the fluid? And just apply hand pressure on the piston to see if it makes any change in the fluid?

 

[AMX364]

Close, with master cylinder cover off, shine light at piston and remove master cylinder mounting nuts. If the valve moves then the brakes are slightly applying. It should not move. If the mater cylinder piston does move the rod is too long, remove about 1/16 of a inch and retest.

If this is the issue it cause funny problems and is a pain to find, easy to fix thoo.

 

[Cornpatch MO]

Close, with master cylinder cover off, shine light at piston and remove master cylinder mounting nuts. If the valve moves then the brakes are slightly applying. It should not move. If the mater cylinder piston does move the rod is too long, remove about 1/16 of a inch and retest.

If this is the issue it cause funny problems and is a pain to find, easy to fix thoo.

Maybe the nuts could just be loosened without completely removing them?
I thought this may be the problem I was having, but in sitting for some time , air worked its way out and my problem solved.
Couldn't a person go to the brake pedal, where the push rod attaches and make sure there is a small amount of play in that push rod before it pushes on the piston? ......................................MO

 

[AMX364]

You would only completely remove the nuts IF the piston moved(shorten the rod). I would still check it, if the piston is slightly engaged you will have problems and they will be "funny" and not in a good way. Also only takes about 5 min. to check. As far as the pedal to feel the play means too loose(too short), different issues, not as bad. pedal needs to travel farther.