Changing from DOT 5 To DOT3 brake fluid FED UP WITH AIR BUBBLES on my 67

[Al R.]

Anyone else got fed up trying to bleed all the air out of DOT 5 fluid and switched back to DOT 3? What issues will I be looking at and how do I ensure I got all the DOT 5 out of the system? Everything is new or rebuilt. 3-4 weekends is enough!!! Can the DOT 5 be blown out of the lines and calipers with air pressure or is there a better way? THANKS!!!

[Dick W.]

Re: Changing from DOT 5 To DOT3 brake fluid FED UP WITH AIR BUBBLES on my 67

I have used DOT 5; since the early '80's with no problems. Don't understand the problems you are having

[David K.]

Re: Changing from DOT 5 To DOT3 brake fluid FED UP WITH AIR BUBBLES on my 67

I have been running DOT 5 since '86. As is said, I did not take apart the brake lines and master/slave cylinders. I did put in Dot 5 and bleed all the cylinders until they were clean of any Dot 3 brake fluid. I did this again a week later and then again the next spring. I have had NO trouble at all. The air that you may see, will settle out if you are really aggressive pumping the brake pedal to bleed the system. Just a nice steady gentle push on the peddle works for me.

[Al R.]

Re: Changing from DOT 5 To DOT3 brake fluid FED UP WITH AIR BUBBLES on my 67

I originally tried gravity flow to fill the lines and calipers, then after fluid started seeping out of bleeders, they were closed off and then with the use of the brake pedal as a pump,the bleeders were opened 1 at a time to bleed out the remainder of the air. This took 4-5 hrs for each of 2 weekend days for 2 weekends before I got a good pedal. Approx 3-4-5 weeks later-- no pedal. I've tried again for roughly 4-5 hrs to rebleed everything including the MC using the above method as well as a vacuum pump with thread tape & axle grease on the bleeders. Today, I've been on it for another 6 hrs with no success. All hoses & lines are tight & have been checked & rechecked for tighteness and fluid leaks. I also checked the play in the pedal travel (approx. 1/4-1/2"). I'm about ready to push the car over into my pond and let the fish use it!! If anyone lives near Smithfield, NC and would like to help/solve I'm willing to pay for your troubles if we can get brakes to stay up. Also open to suggestions. I bought a Motive pressure bleeder after suggestions over on the CF, bur after reading some posts on this site have decided not to use it

[Jim D.]

Re: Changing from DOT 5 To DOT3 brake fluid FED UP WITH AIR BUBBLES on my 67

Sorry you're having a rough time. I'm sure you're frustrated as a he11 but there's got to be something wrong in your system. Like those above, I've been using it in every car I build since the early 80's and have never had a problem bleeding them. Once and done, that was it. I'm sure you know this but, don't shake the bottle and pour it as gently as possible, some advise pouring down the shaft of a screwdriver but I've never needed to. Treat it like it was nitroglycerine. Don't pump the pedal. Open the bleeder, slowly push the pedal down, hold, close the bleeder, release the pedal and repeat.

[Larry M.]

Re: Changing from DOT 5 To DOT3 brake fluid FED UP WITH AIR BUBBLES on my 67

Sorry you're having a rough time. I'm sure you're frustrated as a he11 but there's got to be something wrong in your system. Like those above, I've been using it in every car I build since the early 80's and have never had a problem bleeding them. Once and done, that was it. I'm sure you know this but, don't shake the bottle and pour it as gently as possible, some advise pouring down the shaft of a screwdriver but I've never needed to. Treat it like it was nitroglycerine. Don't pump the pedal. Open the bleeder, slowly push the pedal down, hold, close the bleeder, release the pedal and repeat.

Agree with Jim. Have used DOT 5 in my 1967 car for over 18 years without issue. Have bleed the brakes many times due to various work on the car or brake system. No problems whatsoever. It isn't the DOT 5 fluid.

Larry

[Joe L.]

Re: Changing from DOT 5 To DOT3 brake fluid FED UP WITH AIR BUBBLES on my 67

Anyone else got fed up trying to bleed all the air out of DOT 5 fluid and switched back to DOT 3? What issues will I be looking at and how do I ensure I got all the DOT 5 out of the system? Everything is new or rebuilt. 3-4 weekends is enough!!! Can the DOT 5 be blown out of the lines and calipers with air pressure or is there a better way? THANKS!!!

Al-----


If you're having this problem with DOT 5, I'll bet you're going to have the exact same problem with DOT 3.

I've tested DOT 3 versus DOT 5 with respect to viscosity and tendency to air entrainment. I found no significant difference between the two

[Michael W.]

Re: Changing from DOT 5 To DOT3 brake fluid FED UP WITH AIR BUBBLES on my 67

. Approx 3-4-5 weeks later-- no pedal.

If this loss of pedal is after a good long drive, the problem is not brake fluid. Had someone fiddled around with the brake rotors or rear wheel bearings?

[Dennis O.]

Re: Changing from DOT 5 To DOT3 brake fluid FED UP WITH AIR BUBBLES on my 67

I put DOT-5 in my '68 after a complete system rebuild. The instructions said to heat the brake fluid on the stove to slightly less than boiling to drive the air out. I bought a cheap tea-kettle to do this and was very careful not to jiggle it on the way from the stove to the garage. I carefully poured it into the master cylinder and bled the brakes manually. As I remember, the bleeding process was a pain, but I got it done. The brakes have been fine since then. It was a pain however, and when I did my '67, I used DOT-3. (DO NOT forget to put a tag or some such in a conspicuous place telling what kind of brake fluid is in it.) Bleeding the brakes on the '67 was just as big a pain. Right now, I am starting to think that heating the fluid to drive the air out may be the key to all of this. Anyone have any more information on this?

[Jim D.]

Re: Changing from DOT 5 To DOT3 brake fluid FED UP WITH AIR BUBBLES on my 67

Right now, I am starting to think that heating the fluid to drive the air out may be the key to all of this. Anyone have any more information on this?

I've never done it and I've never had a problem with DOT 5. The OP has an issue with his system,that Joe pointed out, will be a problem regardless of the type of fluid used.

[Al R.]

Re: Changing from DOT 5 To DOT3 brake fluid FED UP WITH AIR BUBBLES on my 67

The car has not been driven, as restoration work is still on-going ( should have long been done, but hard to find the time to finish-- This is the project from H---, as what could go wrong, has). I've never heard of heating the fluid, but I guess it would be worth a try. What do you do about what's already in the lines, MC, and calipers, though? I'm beginning to wonder if something has gone wrong with the MC, such as an internal seal could have been damaged by a rough spot on the casting,etc. The MC was purchased from SSBI.

[David K.]

Re: Changing from DOT 5 To DOT3 brake fluid FED UP WITH AIR BUBBLES on my 67

Never heard of heating it. Then again, I put it in 25yrs. ago and never looked back. About 5 yrs. ago I replaced every brake line and hose on the car, so I did bleed the system then obviously. Again bleed and go.

[Dick W.]

Re: Changing from DOT 5 To DOT3 brake fluid FED UP WITH AIR BUBBLES on my 67

I originally tried gravity flow to fill the lines and calipers, then after fluid started seeping out of bleeders, they were closed off and then with the use of the brake pedal as a pump,the bleeders were opened 1 at a time to bleed out the remainder of the air. This took 4-5 hrs for each of 2 weekend days for 2 weekends before I got a good pedal. Approx 3-4-5 weeks later-- no pedal. I've tried again for roughly 4-5 hrs to rebleed everything including the MC using the above method as well as a vacuum pump with thread tape & axle grease on the bleeders. Today, I've been on it for another 6 hrs with no success. All hoses & lines are tight & have been checked & rechecked for tighteness and fluid leaks. I also checked the play in the pedal travel (approx. 1/4-1/2"). I'm about ready to push the car over into my pond and let the fish use it!! If anyone lives near Smithfield, NC and would like to help/solve I'm willing to pay for your troubles if we can get brakes to stay up. Also open to suggestions. I bought a Motive pressure bleeder after suggestions over on the CF, bur after reading some posts on this site have decided not to use it

If you had posted this a week ago I could have come by, I was in New Bern last weekend.

[Paul S.]

Re: Changing from DOT 5 To DOT3 brake fluid FED UP WITH AIR BUBBLES on my 67

As I posted yesterday, I'm in the process of switching back to DOT4 from DOT 5 (as part of uninstalling CSSB Inc.'s calipers and MC and replacing with new stuff from Lone Star due to continual problems with brake fluid seeping from the right front caliper hose connnection and brake fluid running down the back of the MC). My switch has more to do with the fact that I get a do over and I don't like the cumbersome, time consuming two man bleeding process that comes with DOT 5. Had I known my Motive power bleeder was not going to work with the DOT 5, I would never went down the DOT 5 road.

Switching from DOT 5 to DOT 3/4 is involved if you want to avoid any possibility of cross fluid contamination--e.g., rebuild the calipers and master cylinder to replace all the rubber seals, and flush the brake lines with denatured alcohol (which is easy with the Motive power bleeder--fill with denatured alcohol, pressurize and open the bleeders one at a time and let them drain until it's clear alcohol), and replace the rubber brake lines.

As for your current problems, I was able to bleed the system using gravity bleeding and then switching to two-man traditional method. Bothersome and time consuming, no doubt. Once bled, I didn't find the pedal feel to change after I repeatedly "worked" on right front caliper hose fitting that was weeping brake fluid, and even loosening and reinstalling the master cylinder brake lines to make sure they were not cracked and were seating properly. I didn't re-bleed every time I opened up the lines; I selectively re-bled the system when I thought I had the seeping fixed, to minimize the inconvenience of having my neighbor help me with the two man bleeding process. I did eventually conscript my neighbor to sit through the bleeding process three times over the past two months while trying to solve the "seeping" problems, and only had some relatively minor air.

I cannot imagine you have more entrapped air in the DOT 5 than I had--I used the Motive power bleeder initially which exacerbates the problem with air. I still got all that air out Also, I knew to leave the brake fluid settle in the bottles, with the cap loosened, pouring it slowly. That's about it.

[Al R.]

Re: Changing from DOT 5 To DOT3 brake fluid FED UP WITH AIR BUBBLES on my 67

Thanks Paul, I was able to get some brakes today using the gravity flow method followed up with the husband/wife method. Only able to get about 2'' of pedal above the floor, though. This lasted for only about an hour. I re-checked the pedal after changing plug wires in an effort to eliminate a skip in the engine. When I checked the pedal with the engine running, the pedal went to the floor. I cut off the engine and checked again with the same result. You could get a little brake if you pumped the pedal several times rapidly with the engine off. Either I'm still not getting all the air out or it's sucking air in somewhere. I have about rounded off the bleeders where the wrench fits. Are the bleeders available at local stores or do you get them from the brake people listed in the Driveline?