The Ford Barn

1stford · 03-19-2026, 02:05 PM

Hey everyone,

Wanted to see if anyone might chime in before I started messing with anything. I have a 1941 Mercury 8 Convertible that is fully restored. Never had an issue with the car in the past. I took it out for the 1st nice weather drive about 3 weeks ago and had to have it towed home.

As I got on the freeway I noticed it did not have much pep in its step. The more gas I gave the less it wanted to go, like something was keeping it from moving. It started to over heat and so I pulled over, when I did I tried to step on the brakes and had nothing. The brakes did not go to the floor they just would not press down. I got out, put it in neutral and tried to push it and it felt like the brakes were on.

I waited about a half hour and brakes worked. I had it towed home for safe measure but drove it today and it drove and braked fine short of a Loud squeak now coming from the front drivers side brake.

All that was done this winter was:
Changed the oil
Changed the transmission fluid
Changed the rear end gear oil.

Thanks in advance.

Als48 · 03-19-2026, 02:16 PM

You seem to have a brake cylinder seizing on your front left brake. I've seen wheel bearings fail and cause the brakes to drag, as well so you might need to look into that. The one time i had that happen was on a rear axle, tho.

Al Hook

KiWinUS · 03-19-2026, 02:17 PM

Possibly master cylinder piston is stuck and the push rod has dropped out of hole in piston now holding piston from returning.

glennpm · 03-19-2026, 02:23 PM

A few things to consider.

- Not enough free clearance for master cylinder push rod
- Bad rubber brake hose/s
- Bad wheel cylinder which is not free to return
- Brake shoes too tight and require adjustment

I'd be looking closely at the squeaky RF drum and hose

Kube · 03-19-2026, 06:40 PM

Not master adjustment as the car had been performing well prior to this incident.

My guess? At least one wheel cylinder did not return after being used. Most likely a gummed up cylinder. Moisture does enter the system and after a few years, the cylinders often get gummed up.
Me? I'd pull all cylinders and at the very least, do a quick hone and install all new rubber cups and boots. Flush out all the old fluid and fill / bleed with fresh.

There's a slight chance the hose going to that wheel collapsed internally. You'll know as soon as you inspect that cylinder.
If the hoses are old, I'd replace them at the same time I cleaned up all four cylinders.

Mart · 03-20-2026, 03:35 AM

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As well as the above I would inspect the brake pedal pivots. both at the pedal main pivot and where the pushrod attaches. Have had problems here in the past.

Ggmac · 03-20-2026, 06:08 AM

Was it pulling to one side when you applied the brakes? As suggested replace / rebuild front wheel cyl and replace the rubber hoses all 3 , 2 in front one in rear . Flush brake system . The pulling question should determine which side was the culprit. With some exceptions.

rich b · 03-21-2026, 08:54 PM

First (and easiest) place to check is that the brake pedal is returning fully and allowing the pushrod to fully release the master cylinder piston.

pistonbroke · 03-22-2026, 07:39 AM

I had the same problem it ended up being the master was not letting the fuid return right away. There is a small hole that allows the fluid to retune to the reservoir when the brake pedal is released. This can get plugged with rust or other crud or as stated above the piston is not reurning all the way. Take the cap off your master and push and releas the pedal when you releas it and it has returned completly you should see a squirt back into the reservoir. (set the cap in place while pressing the pedal down or things can get messy) If you don't see the fluid return the hole can be probed with a small wire like a paper clip.

jplutz · 03-23-2026, 05:35 PM

Greetings, something very similar happened to me the first time I drove my car for more than ten miles. The car struggled and then would not move. It was the right wheel cylinder on mine. I had to rebuild the entire brake system, including replacing all the drums. Quite a lesson on my 52. I had a crossover line on the front that was installed backwards, and caused a leak at the right flex line fitting. What a mess.
If your wheel cylinder is corroded inside then you probably have water in the brake fluid. If so then the others may not be far behind. If you do your own work you can save on labor. Good luck, JPL

bobH · 03-23-2026, 06:10 PM

Jeremy.... long time, no....
What Kube said, Mart said, etc. I don't see that anyone mentioned the 'bleed hole' (by-pass port) in the master cylinder. If it somehow got plugged up with crud, it would give the symptoms of locked up brakes (that would automatically relieve themselves in a half hour). Same as having the push rod too long, covering the port. Last one I worked on, it only had a .040 hole, so it doesn't take much crud to plug it. Easy to check, in place, if you have a .040 number drill to poke in there (by hand).
About stuck wheel cylinders.... I don't have the slightest clue if RAK assembled those with assembly fluid. If he used brake fluid, that would explain their being stuck. Some folks overlook that brake fluid is hygroscopic, and should not be used for assembly.
Good to hear from you again. I hope all is going well.

Sid · 03-23-2026, 07:03 PM

I have also seen brake hoses go bad. Fluid moves one way but can not release.. Old hoses come apart on the inside and after a few applications the wheel locks up then after it sets awhile it slowly releases. Next time you drive feel for a hot drum/wheel after driving and applying brakes a few times.

Gene1949 · 03-24-2026, 08:04 AM

Quote:

Originally Posted by Sid

I have also seen brake hoses go bad. Fluid moves one way but can not release.. Old hoses come apart on the inside and after a few applications the wheel locks up then after it sets awhile it slowly releases. Next time you drive feel for a hot drum/wheel after driving and applying brakes a few times.

Happened to me many years ago. Thankfully, had a very astute parts guy/friend who set me straight.

kevinshea · 03-24-2026, 09:15 AM

Also happened to me just a few weeks ago after I moved my car out of long term storage. Due to the long term storage I decided to replace all brake lines and the front cylinders on both sides... Just didn't want to mess around... checked the rears and they looked fine. and of course, reset the shoes on the Lockheed system.

TJ · 03-24-2026, 09:16 AM

How long has it been since you actually worked on the brake system or changed the fluid? If it has been a long time or never done then you need to go over the entire system.

1stford · 05-05-2026, 03:47 PM

Well I'm a bit late in responding! Thanks for the feedback. I plan to look deeper into this in the coming days.

I took it out for a drive about 2 weeks ago and short of the squeak when I hit the brakes hard it all seems to run and drive fine. When this happened I drove it for about 20 minutes before it locked up. I don't believe in things getting better on their own with old cars but if everything seems to be working smoothly what is the best way to confirm a problem?

1stford · 05-05-2026, 03:48 PM

Quote:

Originally Posted by bobH

Jeremy.... long time, no....
What Kube said, Mart said, etc. I don't see that anyone mentioned the 'bleed hole' (by-pass port) in the master cylinder. If it somehow got plugged up with crud, it would give the symptoms of locked up brakes (that would automatically relieve themselves in a half hour). Same as having the push rod too long, covering the port. Last one I worked on, it only had a .040 hole, so it doesn't take much crud to plug it. Easy to check, in place, if you have a .040 number drill to poke in there (by hand).
About stuck wheel cylinders.... I don't have the slightest clue if RAK assembled those with assembly fluid. If he used brake fluid, that would explain their being stuck. Some folks overlook that brake fluid is hygroscopic, and should not be used for assembly.
Good to hear from you again. I hope all is going well.

Hope you are doing well! If this crud gumming up the hole is the issue then after it cleared is the problem fixed?

Drbrown · 05-06-2026, 10:00 AM

Quote:

Originally Posted by 1stford

Well I'm a bit late in responding! Thanks for the feedback. I plan to look deeper into this in the coming days.

I took it out for a drive about 2 weeks ago and short of the squeak when I hit the brakes hard it all seems to run and drive fine. When this happened I drove it for about 20 minutes before it locked up. I don't believe in things getting better on their own with old cars but if everything seems to be working smoothly what is the best way to confirm a problem?

My '47 is behaving the same way i.e. after it sits for a time the system behaves normal. BUt start using the brakes and the system starts sezing up. Upon quick braking, the car does not pull to one side or the other and when siezed and jacked, all the wheels are siezed. So I strongly believe the Master Cylinder is a fault.

Kube · 05-06-2026, 12:09 PM

Quote:

Originally Posted by Drbrown

My '47 is behaving the same way i.e. after it sits for a time the system behaves normal. BUt start using the brakes and the system starts sezing up. Upon quick braking, the car does not pull to one side or the other and when siezed and jacked, all the wheels are siezed. So I strongly believe the Master Cylinder is a fault.

If al wheels are seized, master is at fault.
If one or a couple of wheels are seized it is one or a couple of wheel cylinders.

When things "get better" it is usually a wheel cylinder that is gummed up just enough to hold it back a little and then with some use, it frees up. This "free state" won't last.

tubman · 05-06-2026, 12:42 PM

The '39-'48 Fords seem to be prone to this problem. When I put hydraulic brakes in my first '36 Ford, I got them from a neighbor who had a '46-'48 in his back yard. The brakes on the car still worked, so being 15 years old, I lifted the whole setup and installed it in my car without changing anything but the fluid. When I got them in, they wouldn't bleed. A perusal of the Old man's Motor manual revealed a diagram of flow through the system. It was pretty obvious to me where the problem was. I tried opening up the hole between the reservoir and the cylinder with a piece of wire, but it was blocked pretty good. I distinctly remember running a drill through it, which made everything operational.

I look back at those days and some of the things I did and marvel that I am still alive.

03-19-2026, 02:05 PM	#1
1stford Senior Member Join Date: Sep 2016 Posts: 297	Car seized up Hey everyone, Wanted to see if anyone might chime in before I started messing with anything. I have a 1941 Mercury 8 Convertible that is fully restored. Never had an issue with the car in the past. I took it out for the 1st nice weather drive about 3 weeks ago and had to have it towed home. As I got on the freeway I noticed it did not have much pep in its step. The more gas I gave the less it wanted to go, like something was keeping it from moving. It started to over heat and so I pulled over, when I did I tried to step on the brakes and had nothing. The brakes did not go to the floor they just would not press down. I got out, put it in neutral and tried to push it and it felt like the brakes were on. I waited about a half hour and brakes worked. I had it towed home for safe measure but drove it today and it drove and braked fine short of a Loud squeak now coming from the front drivers side brake. All that was done this winter was: Changed the oil Changed the transmission fluid Changed the rear end gear oil. Thanks in advance. Last edited by 1stford; 03-19-2026 at 02:15 PM.

03-19-2026, 02:16 PM	#2
Als48 Senior Member Join Date: Feb 2020 Location: Paducah Ky Posts: 420	Re: Car seized up You seem to have a brake cylinder seizing on your front left brake. I've seen wheel bearings fail and cause the brakes to drag, as well so you might need to look into that. The one time i had that happen was on a rear axle, tho. Al Hook

03-19-2026, 02:17 PM	#3
KiWinUS Senior Member Join Date: May 2010 Location: Charlotte NC KiWi-L100 available here Posts: 3,415	Re: Car seized up Possibly master cylinder piston is stuck and the push rod has dropped out of hole in piston now holding piston from returning.

03-19-2026, 02:23 PM	#4
glennpm Senior Member Join Date: Sep 2014 Location: Mid-Coast Maine Posts: 3,346	Re: Car seized up A few things to consider. - Not enough free clearance for master cylinder push rod - Bad rubber brake hose/s - Bad wheel cylinder which is not free to return - Brake shoes too tight and require adjustment I'd be looking closely at the squeaky RF drum and hose __________________ Archives of historical but relevant older articles: ------------- Hover mouse over the links below and click! ~~~~~~~~~~~~~~~~~--------------- Rumble Seat’s Notes Techno Source for the 1932 thru 1953 Flathead Ford

03-19-2026, 06:40 PM	#5
Kube Super Moderator Join Date: May 2010 Location: Wisconsin, USA Posts: 10,539	Re: Car seized up Not master adjustment as the car had been performing well prior to this incident. My guess? At least one wheel cylinder did not return after being used. Most likely a gummed up cylinder. Moisture does enter the system and after a few years, the cylinders often get gummed up. Me? I'd pull all cylinders and at the very least, do a quick hone and install all new rubber cups and boots. Flush out all the old fluid and fill / bleed with fresh. There's a slight chance the hose going to that wheel collapsed internally. You'll know as soon as you inspect that cylinder. If the hoses are old, I'd replace them at the same time I cleaned up all four cylinders. __________________ "I can explain it for you. However, I can't understand it for you".

03-20-2026, 03:35 AM	#6
Mart Senior Member Join Date: May 2010 Location: Solihull, England. Posts: 9,239	Re: Car seized up Sponsored Links (Register now to hide all advertisements) As well as the above I would inspect the brake pedal pivots. both at the pedal main pivot and where the pushrod attaches. Have had problems here in the past.

03-20-2026, 06:08 AM	#7
Ggmac Senior Member Join Date: Jul 2016 Location: Lake worth Florida Posts: 1,466	Re: Car seized up Was it pulling to one side when you applied the brakes? As suggested replace / rebuild front wheel cyl and replace the rubber hoses all 3 , 2 in front one in rear . Flush brake system . The pulling question should determine which side was the culprit. With some exceptions.

03-21-2026, 08:54 PM	#8
rich b Senior Member Join Date: May 2010 Location: Minnesota Posts: 2,156	Re: Car seized up First (and easiest) place to check is that the brake pedal is returning fully and allowing the pushrod to fully release the master cylinder piston.

03-22-2026, 07:39 AM	#9
pistonbroke Senior Member Join Date: Feb 2021 Location: Perry Mo. Posts: 838	Re: Car seized up I had the same problem it ended up being the master was not letting the fuid return right away. There is a small hole that allows the fluid to retune to the reservoir when the brake pedal is released. This can get plugged with rust or other crud or as stated above the piston is not reurning all the way. Take the cap off your master and push and releas the pedal when you releas it and it has returned completly you should see a squirt back into the reservoir. (set the cap in place while pressing the pedal down or things can get messy) If you don't see the fluid return the hole can be probed with a small wire like a paper clip.

03-23-2026, 05:35 PM	#10
jplutz Senior Member Join Date: Sep 2021 Location: Marlboro, NY Posts: 137	Re: Car seized up Greetings, something very similar happened to me the first time I drove my car for more than ten miles. The car struggled and then would not move. It was the right wheel cylinder on mine. I had to rebuild the entire brake system, including replacing all the drums. Quite a lesson on my 52. I had a crossover line on the front that was installed backwards, and caused a leak at the right flex line fitting. What a mess. If your wheel cylinder is corroded inside then you probably have water in the brake fluid. If so then the others may not be far behind. If you do your own work you can save on labor. Good luck, JPL

03-23-2026, 06:10 PM	#11
bobH Senior Member Join Date: May 2010 Location: so cal, placerville, vegas Posts: 1,436	Re: Car seized up Jeremy.... long time, no.... What Kube said, Mart said, etc. I don't see that anyone mentioned the 'bleed hole' (by-pass port) in the master cylinder. If it somehow got plugged up with crud, it would give the symptoms of locked up brakes (that would automatically relieve themselves in a half hour). Same as having the push rod too long, covering the port. Last one I worked on, it only had a .040 hole, so it doesn't take much crud to plug it. Easy to check, in place, if you have a .040 number drill to poke in there (by hand). About stuck wheel cylinders.... I don't have the slightest clue if RAK assembled those with assembly fluid. If he used brake fluid, that would explain their being stuck. Some folks overlook that brake fluid is hygroscopic, and should not be used for assembly. Good to hear from you again. I hope all is going well.

03-23-2026, 07:03 PM	#12
Sid Senior Member Join Date: May 2010 Location: Rathdrum Idaho Posts: 780	Re: Car seized up I have also seen brake hoses go bad. Fluid moves one way but can not release.. Old hoses come apart on the inside and after a few applications the wheel locks up then after it sets awhile it slowly releases. Next time you drive feel for a hot drum/wheel after driving and applying brakes a few times.

03-24-2026, 09:15 AM	#14
kevinshea Member Join Date: Apr 2015 Location: old orchard beach maine Posts: 64	Re: Car seized up Also happened to me just a few weeks ago after I moved my car out of long term storage. Due to the long term storage I decided to replace all brake lines and the front cylinders on both sides... Just didn't want to mess around... checked the rears and they looked fine. and of course, reset the shoes on the Lockheed system.

03-24-2026, 09:16 AM	#15
TJ Senior Member Join Date: May 2010 Location: Napa,California Posts: 6,773	Re: Car seized up How long has it been since you actually worked on the brake system or changed the fluid? If it has been a long time or never done then you need to go over the entire system.

05-05-2026, 03:47 PM	#16
1stford Senior Member Join Date: Sep 2016 Posts: 297	Re: Car seized up Well I'm a bit late in responding! Thanks for the feedback. I plan to look deeper into this in the coming days. I took it out for a drive about 2 weeks ago and short of the squeak when I hit the brakes hard it all seems to run and drive fine. When this happened I drove it for about 20 minutes before it locked up. I don't believe in things getting better on their own with old cars but if everything seems to be working smoothly what is the best way to confirm a problem?

05-06-2026, 12:42 PM	#20
tubman Senior Member Join Date: Dec 2013 Location: Minnesota, Florida Keys Posts: 12,132	Re: Car seized up The '39-'48 Fords seem to be prone to this problem. When I put hydraulic brakes in my first '36 Ford, I got them from a neighbor who had a '46-'48 in his back yard. The brakes on the car still worked, so being 15 years old, I lifted the whole setup and installed it in my car without changing anything but the fluid. When I got them in, they wouldn't bleed. A perusal of the Old man's Motor manual revealed a diagram of flow through the system. It was pretty obvious to me where the problem was. I tried opening up the hole between the reservoir and the cylinder with a piece of wire, but it was blocked pretty good. I distinctly remember running a drill through it, which made everything operational. I look back at those days and some of the things I did and marvel that I am still alive.