08 Front brakes under pressure

[ChrisRCNY]

I just picked up an 08 that was used as a police vehicle. I assumed the brakes needed rust removal, but everything is in good shape.

It seems to want to keep the front brakes pressurized. I've not checked the driver's side yet, bit passenger side would only release if I cracked the bleeder.

Starting the engine and pumping the pedal a few times will lock it right back up.

Given the prettyness of the master cylinder, it's possible they replaced it and it's just not releasing. I'm hoping it's the hoses, as they look original.

Does anyone have any other ideas?

 

[ExpeditionAndy]

Welcome to the forum.

Brake hoses have been known to collapse internally causing them to hold pressure. That is probably the first thing I would replace and see if it changes anything.

 

[ChrisRCNY]

That's my current plan. Supposedly the bracket that wraps around the house will rust and constrict the hose a bit. The master cylinder can force fluid in, but it won't return well.

Jacked up driver's side, seems to rotate normally now. Passenger was still locked up tight. I've got both hoses coming in tomorrow, I'll swap them out and pray.

 

[Big Brian]

I would crack the lines going to the fronts at the master to verify the master isnt causing the problem

...which is very doubtful

 

[ExpeditionAndy]

That's my current plan. Supposedly the bracket that wraps around the house will rust and constrict the hose a bit. The master cylinder can force fluid in, but it won't return well.

Jacked up driver's side, seems to rotate normally now. Passenger was still locked up tight. I've got both hoses coming in tomorrow, I'll swap them out and pray.

Do you know the procedure for bleeding the brakes after you change the hoses?

 

[gixer2000]

Welcome to the forum.

Brake hoses have been known to collapse internally causing them to hold pressure. That is probably the first thing I would replace and see if it changes anything.

Bingo!

I just recently had this issue and thought the caliper was stuck. Nope it was a $30 flex hose.

 

[USMCBuckWild]

Flex hoses will definately swell and "collapse" over time. Combination of heat, moisture in fluid and deterioration of fluid; its hard on the rubber liner. Swap the rubber lines (preferably for braided lines with a better quality Teflon or PTFE (polytetrafluoroethylene) equivalent liner) and bleed the entire system. Get all that old fluid replaced with fresh.

 

[Big Brian]

Flex hoses will definately swell and "collapse" over time. Combination of heat, moisture in fluid and deterioration of fluid; its hard on the rubber liner. Swap the rubber lines (preferably for braided lines with a better quality Teflon or PTFE (polytetrafluoroethylene) equivalent liner) and bleed the entire system. Get all that old fluid replaced with fresh.

good points

another common reason they go bad is because people will just let the caliper hang off them when changing the pads and this damages the lines prematurely (it kinks the line where the metal ferrule is crimped on at the hose bracket mount) you should always hang it off a hook made out of a coat hanger or set them on the upper control arm or support them somehow when servicing the pads

the inner lining of the hose can crack and act like a check valve holding fluid in the caliper under pressure. The hose can look fine on the outside but be damaged on the inside

 

[theoldwizard1]

Replacing the brake hose is cheap and easy (Motorcraft left BRHF131, Motorcraft right BRHF66) , but I don't think this is the real problem. Still worth doing. Biggest problem with replacing the brake hose is rust on the fitting on the both ends of the hose AND on the bleeder screw. Likely these will all need a bit of heat from a propane torch.

When replacing the "core" brake parts, I always stay with "top of the line" NAME BRAND parts, like Wagner or Raybestos.

If it was me, along with the hose, I would purchase and install rebuilt caliper, pads and mounting hardware (Raybestos Police left RC11948SV, Raybestos Police RC11945SVP). I don't know if this includes the slider pins, but I would replace them also (Raybestos H5089) .

If the pads have been sticking for awhile, you will probably need a new rotor (Raybestos Police 680508P).

 

[ExpeditionAndy]

Replacing the brake hose is cheap and easy (Motorcraft left BRHF131, Motorcraft right BRHF66) , but I don't think this is the real problem. Still worth doing. Biggest problem with replacing the brake hose is rust on the fitting on the both ends of the hose AND on the bleeder screw. Likely these will all need a bit of heat from a propane torch.

When replacing the "core" brake parts, I always stay with "top of the line" NAME BRAND parts, like Wagner or Raybestos.

If it was me, along with the hose, I would purchase and install rebuilt caliper, pads and mounting hardware (Raybestos Police left RC11948SV, Raybestos Police RC11945SVP). I don't know if this includes the slider pins, but I would replace them also (Raybestos H5089) .

If the pads have been sticking for awhile, you will probably need a new rotor (Raybestos Police 680508P).

That's what I did last summer to my old 05 one of the caliper was sticking so I replaced calipers, pads, rotors, and hoses. I did front and rear because they were original and I got the friends and family discount from my friend and it was way cheaper than anywhere else.