The Ford Barn

Barry in St.Paul · 09-19-2023, 01:49 PM

Hi,
I started my rebuild of my '57 chassis with DOT5 silicone brake fluid. Had a devil of a time getting all the connections to stop weeping, but finally did. Then, discovered the wheel-cylinders have very slight weeps, some DOT5 in the boots while sitting the past couple years (working on OTHER parts of the chassis). The new cylinder had sat for several years in my basement before I got to that part of assembly, there was slight corrosion spotting so I used Scotchbrite on them; I think those very fine scratches are where the darn DOT5 is sneaking past now.

Therefore I need to replace (or hone/kit if I switched to DOT3) my wheel cylinders. In which case, NOW would be the time to switch to the less-difficult DOT 3 if I'm ever going to. All I'd have to do is clean up the M/C and purge the lines with alcohol, and switch is complete.

This is not on my Ford Model-A, but the other club already weighed in ~50/50 (ha!), so thought I'd ask here. Being in Minnesota where cars are parked for at least 6 months of the year, wondering how many of you have switched your cars to DOT5, if you've been glad you did, or if you had any problems with leaks/weeps like I have? (or, how many have good experience to stay away from DOT5?)

I don't intend to start a "which oil is better" type thread here! :-) Just looking to see if there are a lot of successful DOT5 users out there or not, and if you had to do anything special to keep them leak-free.
Thanks!

wellcraft17 · 09-19-2023, 03:15 PM

I put DOT5 in my refurbished 56 F100 with all new US manufactured brake parts in 81or 82. I’ve never had any leaks/issues with my brake system. Don’t know if all my parts that were made in the US have had any bearing on that but I’ve been very happy not to have to work on my hydraulic brake system.

wellcraft17 · 09-19-2023, 03:19 PM

I also put DOT5 in my 54 Willys CJ3B in 2013, same results, no leaks or issues

paul2748 · 09-19-2023, 07:48 PM

I have Dot 5 in my 48 Ford Conv hot rod and 56 Thunderbird and never had any problems , The 48 has been on the road about 40 years. the 56 around 17 years. Did have one fitting on the 56 that gave me trouble at first, but got it solved.

Daves55Sedan · 09-19-2023, 09:45 PM

Decades ago, during restoration when I had body off frame, I replaced all brake lines and hoses with new. Installed new wheel cylinders and master cyl too. Perfect opportunity to switch to DOT5, so I did.
In the years since, I have noticed the level of fluid in the master cylinder decreases about 1/2 inch per year. Not enough of a loss to draw air, so I don't have to bleed the brakes, so I have just left it like that.
I have been under the car several times checking for leaks but can't find any, but thats probably because all frame and suspension parts are shiny black (from the new paint during restoration).
The car has been driven daily, year round so I figure losing 1/2 an ounce of fluid over a years time is tolerable.
I've even had the brake drums off a couple years back during tire change and inspected for leaks at the wheel cylinders. No dice.

Barry in St.Paul · 09-20-2023, 12:00 PM

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Thanks guys. appreciate the input.
Dave, yeah, I'm guessing my long battle with "weeping" at the M/C connections (enough to leave a spot on a clean shop towel), if I'd ignored it, would probably be the same as your long-term loss. Just hateful to know you have a leak (however small) and not FIX IT now, while the body is off and everything so easy to get at.
Good thing I had the drums off 'one last time" to noticed the drip coming out of the wheel cylinder though, I think that would have proven more significant.

New wheel cylinders and proceed with DOT5 I guess! :-)

Ole Don · 09-22-2023, 10:53 AM

After years of Minnesota winters. I have used DOT5 in all my builds, along with two brothers in laws cars. All with no problems. Yes it will evaporate a half ounce a year. I fill it and drive on. I also lived for 16 years in southern Illinois. I used DOT 4 there with good luck.

Gene F · 09-22-2023, 12:40 PM

My neighbor is a big car collector (27 of them), and he told me he put silicone in a car. He told me he thought the pedal felt strange, so he changed it over to DOT3.

My ElCamino, when I changed it over to disc brakes I had everything off of it, and when I put it together I put in straight DOT4. I don't think I have ever added a drop of fluid to that system.

In my 1957 Skyliner, I flush that system with fresh DOT3 about every 6 or 7 years. It's not a big task with a helper. Easier than letting the system deteriorate. When I go that car the fluid looked like mud. LOL

rotorwrench · 09-22-2023, 03:37 PM

DOT 5 has a little bit different compressability characteristics than DOT 3. Both deteriorate at similar rates so both should be flushed & reserviced at regular intervals. I've experienced corrosion with DOT 5 fluid in systems that have cast aluminum components. It takes a little longer but it will eventually absorb moisture. This was the only problem with DOT 3 fluid so I really can't justify changing from one to the other.

Regular scheduled maintenance should be done with any type of brake fluid.

09-19-2023, 01:49 PM	#1
Barry in St.Paul Senior Member Join Date: May 2010 Posts: 118	DOT5 in Minnesota; keep trying or switch to DOT3? Hi, I started my rebuild of my '57 chassis with DOT5 silicone brake fluid. Had a devil of a time getting all the connections to stop weeping, but finally did. Then, discovered the wheel-cylinders have very slight weeps, some DOT5 in the boots while sitting the past couple years (working on OTHER parts of the chassis). The new cylinder had sat for several years in my basement before I got to that part of assembly, there was slight corrosion spotting so I used Scotchbrite on them; I think those very fine scratches are where the darn DOT5 is sneaking past now. Therefore I need to replace (or hone/kit if I switched to DOT3) my wheel cylinders. In which case, NOW would be the time to switch to the less-difficult DOT 3 if I'm ever going to. All I'd have to do is clean up the M/C and purge the lines with alcohol, and switch is complete. This is not on my Ford Model-A, but the other club already weighed in ~50/50 (ha!), so thought I'd ask here. Being in Minnesota where cars are parked for at least 6 months of the year, wondering how many of you have switched your cars to DOT5, if you've been glad you did, or if you had any problems with leaks/weeps like I have? (or, how many have good experience to stay away from DOT5?) I don't intend to start a "which oil is better" type thread here! :-) Just looking to see if there are a lot of successful DOT5 users out there or not, and if you had to do anything special to keep them leak-free. Thanks!

09-19-2023, 03:15 PM	#2
wellcraft17 Senior Member Join Date: Feb 2012 Location: Tampa fl Posts: 133	Re: DOT5 in Minnesota; keep trying or switch to DOT3? I put DOT5 in my refurbished 56 F100 with all new US manufactured brake parts in 81or 82. I’ve never had any leaks/issues with my brake system. Don’t know if all my parts that were made in the US have had any bearing on that but I’ve been very happy not to have to work on my hydraulic brake system.

09-19-2023, 03:19 PM	#3
wellcraft17 Senior Member Join Date: Feb 2012 Location: Tampa fl Posts: 133	Re: DOT5 in Minnesota; keep trying or switch to DOT3? I also put DOT5 in my 54 Willys CJ3B in 2013, same results, no leaks or issues

09-19-2023, 07:48 PM	#4
paul2748 Senior Member Join Date: May 2010 Location: Midland Park, NJ Posts: 3,982	Re: DOT5 in Minnesota; keep trying or switch to DOT3? I have Dot 5 in my 48 Ford Conv hot rod and 56 Thunderbird and never had any problems , The 48 has been on the road about 40 years. the 56 around 17 years. Did have one fitting on the 56 that gave me trouble at first, but got it solved. __________________ 48 Ford Conv 56 Tbird 54 Ford Victoria

09-19-2023, 09:45 PM	#5
Daves55Sedan Senior Member Join Date: May 2010 Location: Granite City, Illinois Posts: 3,008	Re: DOT5 in Minnesota; keep trying or switch to DOT3? Decades ago, during restoration when I had body off frame, I replaced all brake lines and hoses with new. Installed new wheel cylinders and master cyl too. Perfect opportunity to switch to DOT5, so I did. In the years since, I have noticed the level of fluid in the master cylinder decreases about 1/2 inch per year. Not enough of a loss to draw air, so I don't have to bleed the brakes, so I have just left it like that. I have been under the car several times checking for leaks but can't find any, but thats probably because all frame and suspension parts are shiny black (from the new paint during restoration). The car has been driven daily, year round so I figure losing 1/2 an ounce of fluid over a years time is tolerable. I've even had the brake drums off a couple years back during tire change and inspected for leaks at the wheel cylinders. No dice.

09-20-2023, 12:00 PM	#6
Barry in St.Paul Senior Member Join Date: May 2010 Posts: 118	Re: DOT5 in Minnesota; keep trying or switch to DOT3? Sponsored Links (Register now to hide all advertisements) Thanks guys. appreciate the input. Dave, yeah, I'm guessing my long battle with "weeping" at the M/C connections (enough to leave a spot on a clean shop towel), if I'd ignored it, would probably be the same as your long-term loss. Just hateful to know you have a leak (however small) and not FIX IT now, while the body is off and everything so easy to get at. Good thing I had the drums off 'one last time" to noticed the drip coming out of the wheel cylinder though, I think that would have proven more significant. New wheel cylinders and proceed with DOT5 I guess! :-)

09-22-2023, 10:53 AM	#7
Ole Don Senior Member Join Date: May 2010 Location: St. Michael, Minnesota Posts: 1,713	Re: DOT5 in Minnesota; keep trying or switch to DOT3? After years of Minnesota winters. I have used DOT5 in all my builds, along with two brothers in laws cars. All with no problems. Yes it will evaporate a half ounce a year. I fill it and drive on. I also lived for 16 years in southern Illinois. I used DOT 4 there with good luck.

09-22-2023, 12:40 PM	#8
Gene F Senior Member Join Date: Mar 2012 Location: Ohio Posts: 1,975	Re: DOT5 in Minnesota; keep trying or switch to DOT3? My neighbor is a big car collector (27 of them), and he told me he put silicone in a car. He told me he thought the pedal felt strange, so he changed it over to DOT3. My ElCamino, when I changed it over to disc brakes I had everything off of it, and when I put it together I put in straight DOT4. I don't think I have ever added a drop of fluid to that system. In my 1957 Skyliner, I flush that system with fresh DOT3 about every 6 or 7 years. It's not a big task with a helper. Easier than letting the system deteriorate. When I go that car the fluid looked like mud. LOL

09-22-2023, 03:37 PM	#9
rotorwrench Senior Member Join Date: Jun 2010 Location: San Antonio, Texas Posts: 16,440	Re: DOT5 in Minnesota; keep trying or switch to DOT3? DOT 5 has a little bit different compressability characteristics than DOT 3. Both deteriorate at similar rates so both should be flushed & reserviced at regular intervals. I've experienced corrosion with DOT 5 fluid in systems that have cast aluminum components. It takes a little longer but it will eventually absorb moisture. This was the only problem with DOT 3 fluid so I really can't justify changing from one to the other. Regular scheduled maintenance should be done with any type of brake fluid.