2005 TJ rear drum brake problem

[SteveBrown]

Guys,
Sorry, super long post, but if you know something about this subject I would appreciate if you read it:
Finally got my 2005 Jeep TJ brakes together a couple of days ago and I have the exact same problem as I did over the summer.
So, here's what is happening, and I'm hoping someone else has successfully dealt with this:
Chock the front, jack up the rear, apply brakes in 1st or reverse at an idol. This results in in little if any change in engine RPM.
Parking brake does a lot more. I could probably stall the motor if I really yanked on it.
Here is what I replaced:
Master cylinder
Combination valve
All hard hard lines except passenger rear last short segment and passenger front.
All three flexible lines
Rear drums, shoes, cylinders, and most springs & hardware.
A few things didn't come in the kit or didn't physically match, but the olds were serviceable
The rear assembly is exactly as pictured in the Haynes manual and elsewhere, including this site. Adjuster lever properly contacts the wheel on the adjuster screw. I started with manual adjust until some drum drag. Etc
Bench bled the MC and bled all lines starting with passenger rear, driver rear, passenger front, driver front.
Pedal is hard and doesn't pump up.
Additional observations:
I did a test with a drum off to be sure the shoes were even moving. Leading side only moved. I think because of the Ebrake and adjuster hardware on the other side.
Brake released and tried again but no movement. I banged on the combination valve, tried again and movement. Was it time or the banging? IDK
So I suspected the valve or MC was detecting a "failure" and blocking the rear circuit. Put the drum on and did the same test. It would brake the drum once (not very hard), then nothing and hard pedal.
Also, I've done a lot of searching on this and apparently virtually non existent rear brakes is a common problem with TJs.
What I suspect:
The MC section for the rear is not properly sized for the amount of fluid movement required by the drum brakes. So the front piston (for rear brakes) is hitting the limit before the brakes actuate properly.
That's a major WAG, but all I've got at the moment.

 

[Lowcountryearl]

Did you solve this issue?
Been chasing rear drum issues for 6 months, most of the time nothing there and then they wont release and heat up to over 400 degrees

 

[Rubicon88]

Did you solve this issue?
Been chasing rear drum issues for 6 months, most of the time nothing there and then they wont release and heat up to over 400 degrees

Brakes are about as simple as they can be on these Jeeps.

Having said simple is the word too many people don't really understand how to complete the task properly.

The master cylinder must be bench bled. A lot of people think well that's good ...it's bled.... when in fact it isn't bled to completion. It takes a good deal of force with a screwdriver to bleed that in a vice. After many pumps even if you're still getting a bubble or two...it's still not bled.

The other thing is many people want to gravity bleed only. This is an old time way of bleeding by yourself.

You need a helper. Pedal in once (if pressure) open bleed screw...pedal goes to floor. (Helper must keep pressure on the entire time). Helper keeps pedal at floor while the bleed screw screw gets closed. Then release pedal.

Repeat. Until two things. #1 no more air...I mean ZERO...and #2 the fluid is coming out the same color as the new you put in.

A lot of these Jeeps...let's even say the last year for the TJ..is now 15 years old. Thats on the newest of TJ's.
Most are still running around with the original fluid still in it. If not all a great deal of original fluid still powering said brakes.
Hydraulic fluid is no different than other fluids. It will break down over time.

Now back to the rear brakes...both sides should be launching fluid out in nearly the same fashion when bleeding. If one side is a dribble but the other is launching....You've got a blockage/restriction/ wheel cylinder problem at the dribble side. Some type of fluid delivery problem on that side.
Pumping until fresh fluid starts passing through (flushing) is good and can help.

Do NOT allow the master cylinder to go dry.

Same with the front.

Good luck.

 

[MutantNinjaTJ]

05's have disc brakes. The drums are just for the parking brakes and are only cable operated so I'm not sure what you have there on yours. The master Cylinder has nothing to do with the parking brakes.

 

[Goatman]

Always bleed brakes into a clear glass container with the tube from the bleeder submerged in the bledout fluid. His is the only way to be sure there is NO air bubbles. Just watching it spray out is impossible to be sure. There is very little movement of the wheel cylinder needed to achieve pad movement and normally the most contact is from the front shoe. Rear shoe moves when front (least resistance to extend) hits the drum forcing the cyl. To now extend the rear side. Rear has more resistance from springs and E brake. Drum brakes normally adjust themselves from stopping from reverse. Going backwards at a few MPH and hitting the brakes fairly hard a few times should, I repeat, should, adjust them to the correct distance for best braking. They are know to not adjust.
Pulling the Ebrake is a completely different system than the hydraulic brake sys. My guess, and this is just a guess, is that using those old parts (from your nonfunctioning brakes) again in the rebuilt brakes just repeated the reason they didn't work in the first place. Also, front system does somewheres in the area of 70-80% of all braking. Perhaps you are expecting more from the rears than they are designed to do?
There are a lot of guys here (MrBlaine for one) who are truly master brake men. Do EXACTLY everything when and how he says if he responds to this post. He can be 'snarky', but he will be right.

 

[Artsifrtsi]

05's have disc brakes. The drums are just for the parking brakes and are only cable operated so I'm not sure what you have there on yours. The master Cylinder has nothing to do with the parking brakes.

False. I think ONLY the '05s with the Dana 44 (Rubicon) has rear disk brakes. My '05 TJ X has rear drums.

 

[WallyWest]

The hard pedal makes it sound like a Master Cylinder issue. The drum brakes can be totally rusted up, busted hardware, etc... and the pedal will feel fine. I know because that's the condition mine was in when I got it.

You say a few things in your hardware kit didn't fit or match? What things exactly? Do you still have original hardware that hasn't been replaced?

 

[cliffish]

False. I think ONLY the '05s with the Dana 44 (Rubicon) has rear disk brakes. My '05 TJ X has rear drums.

Correct. my 05 X has drum rears, disk fronts

 

[MutantNinjaTJ]

Mine is not a Rubi, It's a Sport but does have a Dana 44 rear. Learn something new here every time I log on.