Brakes issues on my 90 comanche

[Jossue]

Hey there everyone, I've been having a brakes issue with my truck, at first it didn't stop like i had to use a lot of strength on the pedal to feel a bit of brake work and whenever I start it up it works fine, but as I am driving it, it doesn't take much to feel this problem, I feel like the truck gets heavy and it takes a bit to start moving when I'm releasing the clutch. 

So first I changed the booster, which fixed the issue of the truck not braking now it breaks a lot better, but the truck still feels like getting heavy.

I decided to check the drum brakes at the back changed the little cylinders and cleaned the mechanism, also changed the brake main cylinder for a new one but still felt the same issue.

After those changes, I lifted the truck and noticed that after some driving the front wheel are stuck the don't spin nothing, tried to make them spin with my arms but I wasn't able to do it.

So now I know the front wheels of brakes are getting stuck after some use, has someone got any issue like this? I am thinking that maybe the brake proportioning valve is not working well but haven't found any.

If someone has any idea of what could be happening or know where to get a new proportioning valve would thank you a lot.

BTW it is a 1990 comanche 4.0 with no 4x4. Ill look forward to post some photos on the projects in this next weeks.

[Pete M]

I'm literally in the middle of caliper replacement on my Liberty due to stuck brakes.  they don't last forever.  

[llhat]

sounds like...   caliper piston sticking,  not retracting in the caliper bore.

 

Internal residual valve located in master cylinder...    

 

Also mentioned a booster change...   are you sure the actuator rod from the booster to the master cylinder is adjusted correctly?

If it extends too far,  the valving in the master cylinder can block pressure return.

 

One test on brake pressure..  when the wheel is 'locked up'  loosen the bleeder screw to see if there's a lot of pressure there

if the wheel releases,  then see above on booster change...  if not then I'd say piston sticking in the bore.

 

[89 MJ]

I was going to say what has already been said, but also, check your rubber brake lines. The break down over time and will let fluid get to the caliper, but will not let it return from the caliper. If you let the truck sit and it rolls fine, but then after use the brakes get stuck more and more, I would lean towards it being the rubber lines. 

[Eagle_SX4]

4 minutes ago, 89 MJ said:

If you let the truck sit and it rolls fine, but then after use the brakes get stuck more and more, I would lean towards it being the rubber lines. 

I agree with this, those old rubber lines can cause issues. 

[llhat]

ditto on the flexible lines

[pizzaman09]

I have this problem on my 90 occasionally.  I changed the front lines but it didn't do anything, next up is replace the calipers.  Every vehicle I've ever owned has had this issue...   It's the bane of my existence.

[Jossue]

Hey there everyone apparently it got solved, thanks to everyone, apparently it was some of the booster actuator rod adjustments and some brake front line bleeding to get rid of some dirt and other stuff that was in the line.

Againg thanks to evryone, ill still look out for some calippers change.

On 7/9/2025 at 10:11 AM, llhat said:

sounds like...   caliper piston sticking,  not retracting in the caliper bore.

 

Internal residual valve located in master cylinder...    

 

Also mentioned a booster change...   are you sure the actuator rod from the booster to the master cylinder is adjusted correctly?

If it extends too far,  the valving in the master cylinder can block pressure return.

 

One test on brake pressure..  when the wheel is 'locked up'  loosen the bleeder screw to see if there's a lot of pressure there

if the wheel releases,  then see above on booster change...  if not then I'd say piston sticking in the bore.