FJ62 Brakes getting stuck (2 Viewers)

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echodeuce

echodeuce

LC Fiend
Joined
Oct 3, 2016
Threads
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191
Location
South Texas
Brakes are fine for the first 5 minutes or so when I first leave the house. Brake pedal has its usual give and brakes function as they should. After I drive for a bit and it warms up, the brake pedal becomes stiff with no give. Engine is noticeably pushing through what seems to be stuck brakes. I’ll let it sit for a while and back to normal. Once I drive it again, the cycle starts all over again. Thoughts?
 
I'd start by checking the for a vacuum leak at the brake booster, and also the vacuum line going to the booster. My reasoning is that these are things that could cycle from normal to faulty depending on vacuum/vacuum leak.

So no wheel is overheating or smoking? I'm guessing if a brake shoe or pad were stuck ...that it would stay stuck.


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Check your soft lines. If they're old they can look fine but they'll sometimes swell internally. This basically creates a check valve, lets you push fluid to the wheel cylinders or calipers but it won't flow back.
 
Drive it around until the brakes are sticking then jack up the front end and verify the wheels are hard to turn. With it still jacked up loosen the bolts between the booster and master cylinder, if they release it's in the booster. If they don't release loosen the brake line at the master cylinder to see if the brakes release. If they do the problem is in the master cylinder.
 
poptart said:
Check your soft lines. If they're old they can look fine but they'll sometimes swell internally. This basically creates a check valve, lets you push fluid to the wheel cylinders or calipers but it won't flow back.
Click to expand...

This. I had a 76 Chevy truck I bought from a family friend type construction company. It started doing this. I said something to Paul who had an immediate answer. His brother Art - self taught fricking genius of all things mechanical - said to look at the flex brake line brackets. He said they rust and therefore thru rust jacking pinches the flex line shut. The master cylinder has pressure to push fluid thru the restriction but the fluid can't find it's way back quickly enough resulting in stuck brakes. Sure enough pried open the rusted bracket problem solved.
 
Hi, How many miles are on that booster? How old are the calipers? Mike
 
The symptoms are oddly identical to either a poorly adjusted brake booster rod (between booster and master) and/or brake pedal rod/brake switch adjustment issue.
Since you did not mention working on either of those I think the comments regarding backflow sound solid.
 
EscapeWagon62 said:
The symptoms are oddly identical to either a poorly adjusted brake booster rod (between booster and master) and/or brake pedal rod/brake switch adjustment issue.
Since you did not mention working on either of those I think the comments regarding backflow sound solid.
Click to expand...
Funny you mentioned that. I had the little rubber nipple that presses the rear brake light switch tear. I stuck a nickel in there so the rear brake lights would shut off. I have the rubber piece, I just haven’t installed it yet.

Could that possibly be doing something??
 
It absolutely would. My bet is that your pedal rod/freeplay was set based on an old concave brake pedal cushion.
Simple adjustment, loosen the 12mm (or 14 I cant remember) hex nut on the rod and turn the rod counter -clockwise (from the perspective of the drivers seat looking at the firewall.
There needs t be a bit of freeplay in the brake pedal. Without freelay, the brake master engages slightly due to heat expansion of the fluid.
Your first couple brake applications of the day will feel slightly mushy, after that they will be firm.
Simple fix.
 
echodeuce said:
Funny you mentioned that. I had the little rubber nipple that presses the rear brake light switch tear. I stuck a nickel in there so the rear brake lights would shut off. I have the rubber piece, I just haven’t installed it yet.

Could that possibly be doing something??
Click to expand...
Not at all,

mess with the soft lines, had that same penny in there for over 60k miles on my s*** box
 
If memory serves, and it often doesn't, if it was the push rod the pressure would not subside after sitting for a while. You would need to open a fitting to relieve the pressure and release the shoes.
Maybe, perhaps, waiting could work if the master was going bad.
 
archtimb said:
If memory serves, and it often doesn't, if it was the push rod the pressure would not subside after sitting for a while. You would need to open a fitting to relieve the pressure and release the shoes.
Maybe, perhaps, waiting could work if the master was going bad.
Click to expand...
I've had the situation where the rod was set and brakes were fine until they warmed up then dragged after warmup.
Don't know if that is due to expansion of brake pressure after warm up or expansion of brake components after warm up but either way the adjustment of the pedal rod solved it.
My brake pedal cushion was worn like a bowl and I had the pedal set pretty tight to it. When the cushion failed (and brake lights stayed on since the switch plunger pushed right through the pedal arm) I put in a nicklel, Brakes started dragging day one.
Realistically it was all because I didn't have the correct pedal freeplay set to begin with, the small delta was enough to slightly engage the brake booster.
 
Found this forum due to a similar experience after getting my girl back on the road after an engine swap (3FE to 3FE). She rolls fine when cool then the brakes seem to drag and the engine works way to hard. When put in neutral and on a hill, she won't roll when warm/hot and all rims are hot to the touch.

Curious to know if anyone has a solution or can point me in the right direction. TIA

Skooty Skoo
1989 FJ62
 
echodeuce said:
Brakes are fine for the first 5 minutes or so when I first leave the house. Brake pedal has its usual give and brakes function as they should. After I drive for a bit and it warms up, the brake pedal becomes stiff with no give. Engine is noticeably pushing through what seems to be stuck brakes. I’ll let it sit for a while and back to normal. Once I drive it again, the cycle starts all over again. Thoughts?
Click to expand...
I am having the same issue after swapping engine with a donor. If you were able to solve the issue, will you share with me what did the trick?
 
I had brakes drag and overheat.
My issue was the setting on the brake booster rod going to the brake master.
If your pedal starts to feel "harder" and have less "play" after driving for a bit, this is a likely culprit. The other likely culprit is rear shoes set too tight to begin with and getting worse as they heat up.

My bet is your rod setup.
If it is not set correctly, it puts pressure on your brake master and that pressure increases as your system heats up (brake fluid expands) and applies more pressure to your brake master (system acts like you are applying brakes.
It is a very simple adjustment though somewhat of a pain to remove the brake master from the brake booster as you don't want to bend any of your brake hard lines.
Several writeups on this forum on proper brake booster setup.
If you don't have the tool to designed for setting proper brake booster rod length, go to my thread and you can see a homemade version I created using insulation foam and a tube from a WD40 can
Page 9 post 164 though I would recommend spending the $15 to get an actual brake booster setup tool
EscapeWagon62

Builds Thread 'The Escape Wagon Restoration'

I’m finally pulling together all of my projects into one place.
For background I bought this rig about 18 months ago after semi looking for years. I happened to find a 1988 locally which had been well maintained and had good bones (no rust)

My mission was to create a bone stock (or as close as I could accomplish) truck which was reliable enough for cross country adventures (and eventually be my retirement vehicle), comfortable and with some basic modern features like Bluetooth.

Prior to buying it, the most I had ever done was change oil and flat tires. With the help of all of you and a...
  • Like
 
There are several threads on this topic but I will summarize below the steps that I would take to get to the root cause of the issue:

Baseline your braking system:
1. Inspection all soft lines, R&R as required
2. Check pads and shoes for proper thickness and normal wear, R&R as required
3. Check rear e-brake cable and adjust to factory specification per FSM
4. Check rear e-brake bell cranks and adjust to factory specification per FSM
5. Check rear drum adjustment per FSM
6. Check pedal adjustment and confirm brake switch is allowing pedal return per FSM
7. Check Booster to Master cylinder rod measurement per FSM
8. Bleed braking system (Order: Left Rear, Right Rear, Left front, right front for LHD vehicles).

Once this has been completed and you find no issues, then I would move on to the following:
1. Confirm rear pistons are expanding and retracting properly with no fluid leaks
2. Confirm front calipers are working and exerting even force from side to side.
3. Confirm all mounting points are to spec (some of us have found stripped threads on the front knuckles. This can be fixed with heli-coils or Time Certs).
4. Confirm Master cylinder and rear proportioning valve are operating correctly.
5. Confirm Booster is working correctly.

I’ve put these items in the order of operations that I would follow.

Good luck and let us know how it goes.

Cheers, James
 
EscapeWagon62 said:
I had brakes drag and overheat.
My issue was the setting on the brake booster rod going to the brake master.
If your pedal starts to feel "harder" and have less "play" after driving for a bit, this is a likely culprit. The other likely culprit is rear shoes set too tight to begin with and getting worse as they heat up.

My bet is your rod setup.
If it is not set correctly, it puts pressure on your brake master and that pressure increases as your system heats up (brake fluid expands) and applies more pressure to your brake master (system acts like you are applying brakes.
It is a very simple adjustment though somewhat of a pain to remove the brake master from the brake booster as you don't want to bend any of your brake hard lines.
Several writeups on this forum on proper brake booster setup.
If you don't have the tool to designed for setting proper brake booster rod length, go to my thread and you can see a homemade version I created using insulation foam and a tube from a WD40 can
Page 9 post 164 though I would recommend spending the $15 to get an actual brake booster setup tool
EscapeWagon62

Builds Thread 'The Escape Wagon Restoration'

I’m finally pulling together all of my projects into one place.
For background I bought this rig about 18 months ago after semi looking for years. I happened to find a 1988 locally which had been well maintained and had good bones (no rust)

My mission was to create a bone stock (or as close as I could accomplish) truck which was reliable enough for cross country adventures (and eventually be my retirement vehicle), comfortable and with some basic modern features like Bluetooth.

Prior to buying it, the most I had ever done was change oil and flat tires. With the help of all of you and a...
  • Like
Click to expand...
Had the same issue, readjusted with more clearance and no problems since
 
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