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Transmission parking brake rebuild
I can knock another item off the bucket list, rebuilding a ZF transmission mounted, parking brake.
This type of brake was used on the E350 and E450 up until 2008.

Over the years, the parking brake has been left on a few times for short distances.
The last few years, it's effectiveness has not been great, it would hold the rig on a hill but used all the travel available, even after adjusting the cable.
When the transmission was rebuilt a couple weeks ago, the parking brake assembly was temporaily removed.
While off the transmission, the mechanic opened the brake's fill plug and let it drain. What came out was dark and very thick, for transmission fluid.
It was cooked. I have twice previously pumped fresh fluid, into the brake's fill hole, in an attempt to flush out the used oil.

After taking a good look at the brake, it seemed that rebuilding it myself was possible.
An internet search found one poor write up and a PDF, from a technical manual, showing how to rebuild it and
more importantly, providing the end play specifications.
Any part of the brake can be replaced, available from All State Gear.
Online Manual Transmission Rebuild Kits & Transfer Case Parts Supplier
Parts
Manual Transmission Parts - Online - ZF Parking Brake Parts
New parking brake assembly
ZF E-Brake Assembly, ZFBD-R2
Interesting to see that a new unit cost $800, instead of the $1200-1400 I have heard of people paying, that may or may not have included installation, which should add a couple hundred dollars or so.
I bought the 'complete' rebuild kit and a shim set (which should be a part of the kit).
ZF E-Brake Rebuild Kit, ZFBD-KIT
ZF E-Brake Shim Select Kit, ZFBD-S1
Surprised to find that certain Ford F-series pickups also used this type of brake.

Yesterday morning, after unbolting the driveshaft and tying it aside, the parking brake was removed, a simple job made difficult by having to do it laying on my back.
How I wish for a lift. The bolts were rusty and didn't come out easily.

Disassembly was difficult, having to loosen the 2-9/16" nut, with a Factory torque of 220-ft/lbs.
Once the nut was removed, the outer roller bearing and seal popped right out. The rear bearing needed to be pressed off and required a bigger bearing separator than I had. This hung things up a bit while I figured out a fix.
Once the bearing was off, the brake linings became visible and what a shock. They looked liked they have spent a few hours in a furnace, I have never seen brake linings any more heat damaged.
No wonder the parking brake wasn't strong.
Examining the bearings, they showed signs of overheating and discoloring...yikes.
Just driving the LD a few times with the parking brake on, for short distances, was enough to burn up the linings and overheat the small amount of lubricant (only 3 or 4oz). Even after being drain and refilled with fresh oil, two weeks ago, what came out was still very dirty.
I wonder how many other LD's have parking brake in the same condition?
I was happy I had bought a full rebuild kit, instead of just buying the linings and new seals.

Reassembly was straight forward, similar to rebuilding a simple transmission or gear box. The the only complicated part was setting the correct end play. Tapered roller bearings need a little bit of play to account for expansion, when hot.  The new bearings required a slight thicker shim pack, to provide the factory end play of .0019" to .0039".  After several tries, a clearance of .0025 was achieved. After final assembly, it was filled with synthetic transmission oil, same as the transmission .
To ease the installation, the brake assembly's threads were chased and the bolts were wire brushed, to remove any rust.
E450 parking brake rebuild | Flickr

Is this a project you should consider? Probably not, it requires precision measuring tools, a hydraulic press and enough skill and the experience to go about it. The brake is heavy and a PIA to take out and put in. There are no good videos or online tutorials, other than the one PDF. I know a few of you are capable of taking this project on.
http://ww2.justanswer.com/uploads/molurch/2008-03-12_095729_brake.pdf

I'm happy to have done this once and even happier to have found and replaced a lot of damaged parts.
If a parking brake's bearings fail, they can seize, destroying the brake assembly and, many times, destroying the transmission, at the same time.
Total cost, including the purchase of a huge 2-9/16", 3/4"drive socket, was about $150 and very long day.

Does your LD have this issue? Check the parking brake's oil...if you can find the fill hole. If the oil is thin and reddish, it's probably OK. 
If the oil is dark and thick, that's a good sign it has been subjected to high heat. At least try to flush the old oil out and refill.

Larry
Larry
2003 23.5' Front Lounge, since new.  Previously 1983 22' Front Lounge.
Tow vehicles  2020 Jeep Wrangler Rubicon, 2001 Jeep Cherokee
Photo Collection: Lazy Daze
Re: Transmission parking brake rebuild
Reply #1 –
Quote from: Larry Wade  - 
I can knock another item off the bucket list, rebuilding a ZF transmission mounted, parking brake.
This type of brake was used on the E350 and E450 up until 2008.

Over the years, the parking brake has been left on a few times for short distances.
The last few years, it's effectiveness has not been great, it would hold the rig on a hill but used all the travel available, even after adjusting the cable.
When the transmission was rebuilt a couple weeks ago, the parking brake assembly was temporaily removed.
While off the transmission, the mechanic opened the brake's fill plug and let it drain. What came out was dark and very thick, for transmission fluid.
It was cooked. I have twice previously pumped fresh fluid, into the brake's fill hole, in an attempt to flush out the used oil.

After taking a good look at the brake, it seemed that rebuilding it myself was possible.
An internet search found one poor write up and a PDF, from a technical manual, showing how to rebuild it and
more importantly, providing the end play specifications.
Any part of the brake can be replaced, available from All State Gear.
Online Manual Transmission Rebuild Kits & Transfer Case Parts Supplier
Parts
Manual Transmission Parts - Online - ZF Parking Brake Parts
New parking brake assembly
ZF E-Brake Assembly, ZFBD-R2
Interesting to see that a new unit cost $800, instead of the $1200-1400 I have heard of people paying, that may or may not have included installation, which should add a couple hundred dollars or so.
I bought the 'complete' rebuild kit and a shim set (which should be a part of the kit).
ZF E-Brake Rebuild Kit, ZFBD-KIT
ZF E-Brake Shim Select Kit, ZFBD-S1
Surprised to find that certain Ford F-series pickups also used this type of brake.

Yesterday morning, after unbolting the driveshaft and tying it aside, the parking brake was removed, a simple job made difficult by having to do it laying on my back.
How I wish for a lift. The bolts were rusty and didn't come out easily.

Disassembly was difficult, having to loosen the 2-9/16" nut, with a Factory torque of 220-ft/lbs.
Once the nut was removed, the outer roller bearing and seal popped right out. The rear bearing needed to be pressed off and required a bigger bearing separator than I had. This hung things up a bit while I figured out a fix.
Once the bearing was off, the brake linings became visible and what a shock. They looked liked they have spent a few hours in a furnace, I have never seen brake linings any more heat damaged.
No wonder the parking brake wasn't strong.
Examining the bearings, they showed signs of overheating and discoloring...yikes.
Just driving the LD a few times with the parking brake on, for short distances, was enough to burn up the linings and overheat the small amount of lubricant (only 3 or 4oz). Even after being drain and refilled with fresh oil, two weeks ago, what came out was still very dirty.
I wonder how many other LD's have parking brake in the same condition?
I was happy I had bought a full rebuild kit, instead of just buying the linings and new seals.

Reassembly was straight forward, similar to rebuilding a simple transmission or gear box. The the only complicated part was setting the correct end play. Tapered roller bearings need a little bit of play to account for expansion, when hot.  The new bearings required a slight thicker shim pack, to provide the factory end play of .0019" to .0039".  After several tries, a clearance of .0025 was achieved. After final assembly, it was filled with synthetic transmission oil, same as the transmission .
To ease the installation, the brake assembly's threads were chased and the bolts were wire brushed, to remove any rust.
E450 parking brake rebuild | Flickr

Is this a project you should consider? Probably not, it requires precision measuring tools, a hydraulic press and enough skill and the experience to go about it. The brake is heavy and a PIA to take out and put in. There are no good videos or online tutorials, other than the one PDF. I know a few of you are capable of taking this project on.
http://ww2.justanswer.com/uploads/molurch/2008-03-12_095729_brake.pdf

I'm happy to have done this once and even happier to have found and replaced a lot of damaged parts.
If a parking brake's bearings fail, they can seize, destroying the brake assembly and, many times, destroying the transmission, at the same time.
Total cost, including the purchase of a huge 2-9/16", 3/4"drive socket, was about $150 and very long day.

Does your LD have this issue? Check the parking brake's oil...if you can find the fill hole. If the oil is thin and reddish, it's probably OK. 
If the oil is dark and thick, that's a good sign it has been subjected to high heat. At least try to flush the old oil out and refill.

Larry
Oh, my, Larry. I am so totally in awe of your mechanical skills!
Chris
Formerly: 2002 30' IB
Re: Transmission parking brake rebuild
Reply #3 –
Larry, maybe I missed it somewhere (we're on the road) but I'd be interested in hearing more about your decision to have your transmission rebuilt/replaced. Our motorhomes are the same year and I think around the same mileage and of course I have a lot of respect for your knowledge about these matters, so I'm naturally wondering about the implications for our transmission, which seems to run fine, but past automatics have often done the same right up until they didn't.

I've done some research online and find information about the longevity of these 4R100 transmissions that is all over the map, from early failures due to manufacturing defects, especially in the 2000-2001 range, to early failures due to inability to deal with engines with power modifications, to many units that have gone well over 200K miles. Makes it hard to come up with a strategy.

Since I hope to make this our last motorhome and to drive it another 100K miles at least, one thought is that, if the transmission is going to be replaced at some point anyway, why not do it sort of in the middle of our eventual total mileage rather than toward the end.

Anyway, your thoughts would be appreciated. And to the rest of you, who else has replaced or rebuilt your transmission, at what age and mileage and why?

Terry
2003 26.5' RB with just over 100K miles
Gardnerville, NV (now in Yosemite valley)
Terry
2003 26.5'RB
Gardnerville, NV
 
Re: Transmission parking brake rebuild
Reply #4 –
Quote from: Terry Burnes  - 
Our motorhomes are the same year and I think around the same mileage and of course I have a lot of respect for your knowledge about these matters, so I'm naturally wondering about the implications for our transmission, which seems to run fine, but past automatics have often done the same right up until they didn't.

Since I hope to make this our last motorhome and to drive it another 100K miles at least,
Terry

Wish I had a strategy concerning this.
Our transmission was serviced every 30,000 miles, per the Owner's Manual, and fully flushed (18 qts), rather than partially flushed (8 qts), each time.
The transmission's pan was clean when it was pulled at 90,000 miles for a filter change
I installed an oversize cooler several years ago and never overheated it.
Thought these measures might help prolong the life of the transmission beyond a 100,000 miles but it didn't.
I asked John Wood about the life of these transmissions and he responded that they varied but for a GCWR of 18,000-lbs, a 100,000 mile life was not abnormal. The Power-Stroke diesels, used in Ford pickups, tore them up much faster, when pulling comparable weights.

As to when to replace the transmission, much depends on your long term plans and personal finances.
Your rig is in excellent shape and you plan on keeping it for a few more years. It fits you well and don't seem to desire slides.
Replacing it on your schedule sure beats having it die 700 miles from home, when you must be home in three days.
IMO, It's better to have time to research your best replacement choice rather than having to accept whatever is available at the time.

Our situation is similar, the LD works well for us and has all the extra stuff we want is already done.
To upgrade to something bigger and newer would cost a $100,000 or more and take me a couple of years to fit it out.
Spending 5% of that for new transmission doesn't seem to be a bad choice.
I would rather spend the money on travel.
Having replace the transmission has provided some piece of mind, listening to the whine slowly increased in volume, over the last few thousand miles, was an incentive to get it fixed.  Glad I didn't wait too long, there was a failing bushing.
The rebuilt transmission does feel nice, with more positive shifts but not harsh at all. It's also now filled with synthetic fluid, for what that is worth.

Surprisingly, after recently rebuilding the parking brake, the overall driveline noise is down and it feels a little smoother.
It's bearings were worn and evidently were noisy. 

Who knows, your transmission may last 200,000 miles. Wish I knew but my crystal ball is a little cloudy today.

See you at Live Oak.
Larry
Larry
2003 23.5' Front Lounge, since new.  Previously 1983 22' Front Lounge.
Tow vehicles  2020 Jeep Wrangler Rubicon, 2001 Jeep Cherokee
Photo Collection: Lazy Daze