Just installed new hard brake lines, proportioning valve connections were bone dry

Vtx531

Vtx531

TJ Addict
Joined
Nov 17, 2020
Messages
1,661
Location
Kalamazoo, MI
Is that normal? My Jeep has been sitting for a long time (6 months+).

I thought I would crack the bleeders and let the lines gravity bleed but it doesn't seem like that would work with the proportioning valve connections being dry. Should that whole thing be filled with fluid? I guess I'm just not familiar with the system and how it works. The reservoir is full.

Not opposed to vacuum bleeding if that's what I need to do but I thought the fluid should just flow through and come out if I am patient? Not interested in pressure bleeding if I don't have to.
 
Vtx531 said:
Is that normal? My Jeep has been sitting for a long time (6 months+).

I thought I would crack the bleeders and let the lines gravity bleed but it doesn't seem like that would work with the proportioning valve connections being dry. Should that whole thing be filled with fluid? I guess I'm just not familiar with the system and how it works. The reservoir is full.

Not opposed to vacuum bleeding if that's what I need to do but I thought the fluid should just flow through and come out if I am patient? Not interested in pressure bleeding if I don't have to.
Click to expand...

All the connections should drip or leak fluid with the lines removed. Did you have the cap off of the reservoir? If so and no fluid ran out, then I suspect the bore on the master is low or dry and a bench bleed is in order.
 
  • Like
Reactions: IJK
mrblaine said:
All the connections should drip or leak fluid with the lines removed. Did you have the cap off of the reservoir? If so and no fluid ran out, then I suspect the bore on the master is low or dry and a bench bleed is in order.
Click to expand...
I didn't have the cap off when I replaced the lines but I did pull it off in my attempt of the gravity bleed. Should I leave the cap off, let it sit for a while with one of the bleeders cracked and see what happens?
 
I assume there is a reason that a "bench bleed" can't be done with the MC installed in the vehicle? Otherwise it looks like I route some output lines into the reservoir and press the brake pedal repeatedly until no bubbles?
 
Vtx531 said:
I assume there is a reason that a "bench bleed" can't be done with the MC installed in the vehicle? Otherwise it looks like I route some output lines into the reservoir and press the brake pedal repeatedly until no bubbles?
Click to expand...

There is a reason they don't call it the "in the vehicle mounted to the firewall" bleed.
 
  • Like
  • Haha
Reactions: NskLJ and Vtx531
Vtx531 said:
I assume there is a reason that a "bench bleed" can't be done with the MC installed in the vehicle? Otherwise it looks like I route some output lines into the reservoir and press the brake pedal repeatedly until no bubbles?
Click to expand...

You don't understand, bench bleeding is a right of passage, not something based on science. A Bench Bleeder will pump that MC until there is no more bubbles, then remove his bleed lines and let who knows how much air back into the MC.

The real difference is that on vehicle bleed takes two people and a bench bleed just take one guy.

Let the attacks start , I just butchered another sacred cow.😎
 
IJK said:
You don't understand, bench bleeding is a right of passage, not something based on science. A Bench Bleeder will pump that MC until there is no more bubbles, then remove his bleed lines and let who knows how much air back into the MC.

The real difference is that on vehicle bleed takes two people and a bench bleed just take one guy.

Let the attacks start , I just butchered another sacred cow.😎
Click to expand...

Guessing you don't bench bleed using the plugged port method?
 
IJK said:
Do you mean the hurry up put a plug in the port before more brake fluid runs out and air runs in method?
Click to expand...

Not even close. The ports are plugged and then bled like a caliper sorta. Starting with the rear port, open plug, push plunger in, close port and use vacuum to pull fluid into the bore. Repeat until fluid is present at port, close and move to the front port. Repeat until fluid is present there. Once fluid is present at both plugged ports, push the plunger in repeatedly until it will only move in about 1/8".

The small distance is the amount the cup seals move in the bore to cover the replenishment ports to build pressure and push fluid out to the wheel cylinders (not a typo).

What this method does that no other method can do is diagnose the efficacy of the master to check for viability. If you can't get fluid at one or both ports, the master has a problem. If it won't come up and continues to stroke in further than the 1/8" to cover the ports, that tells you there is the likelihood of a damaged seal.

You can't do all of that with other methods plus, it literally only takes about 10-15 strokes of the plunger to fully bench bleed it this way and typically is a sub 3 minute process.

Also, with the ports plugged, you can carry the master over to the rig, install it on the booster, remove one plug at a time to install the lines to the combo valve and at most, you lose a few drops of fluid and zero air goes into the bore.

I've used that method at least a 100 times with zero issues. Fast, easy, 100% effective at both bleeding the master and diagnosing it for issues at the same time.

As much as I'd like to take credit for it, all I'm doing is relating the instructions included in all the Dorman masters we use. ;)

FYI- very much like gravity bleeding calipers, if fluid is going out, air isn't going in until the reservoir is dry.
 
Last edited:
  • Like
  • USA Proud
Reactions: txbemis69 and CharlesHS
mrblaine said:
Not even close. The ports are plugged and then bled like a caliper sorta. Starting with the rear port, open plug, push plunger in, close port and use vacuum to pull fluid into the bore. Repeat until fluid is present at port, close and move to the front port. Repeat until fluid is present there. Once fluid is present at both plugger ports, push the plunger in repeatedly until it will only move in about 1/8".

The small distance is the amount the cup seals move in the bore to cover the replenishment ports to build pressure and push fluid out to the wheel cylinders (not a typo).

What this method does that no other method can do is diagnose the efficacy of the master to check for viability. If you can't get fluid at one or both ports, the master has a problem. If it won't come up and continues to stroke in further than the 1/8" to cover the ports, that tells you there is the likelihood of a damaged seal.

You can't do all of that with other methods plus, it literally only takes about 10-15 strokes of the plunger to fully bench bleed it this way and typically is a sub 3 minute process.

Also, with the ports plugged, you can carry the master over to the rig, install it on the booster, remove one plug at a time to install the lines to the combo valve and at most, you lose a few drops of fluid and zero air goes into the bore.

I've used that method at least a 100 times with zero issues. Fast, easy, 100% effective at both bleeding the master and diagnosing it for issues at the same time.

As much as I'd like to take credit for it, all I'm doing is relating the instructions included in all the Dorman masters we use. ;)

FYI- very much like gravity bleeding calipers, if fluid is going out, air isn't going in until the reservoir is dry.
Click to expand...

Now that is some information the reader can learn from and use. Thanks
 
Top Bottom
Back