How To PERMANENTLY fix your W20-W22 Brakes

[Mutha]

Here is a short tutorial on how to PERMANENTLY fix your Workhorse Re-Called Bosch 66mm Pin Slide Brakes on W-20 Thru W-22 Chassis:

CHANGE THEM TO THE 73mm Bosch Pin Slide Calipers and Pads.

The 73mm Calipers have NEVER had a recall, they are used on all Navistar (IHC) School bus Chassis over 26000 Lbs GVWR with Hydralic brakes -1998 thru Current Production;
All Ford F650 Chassis 2004 thru Current Production;
All Navistar (IHC) 3700 thru 4700 Medium Duty Trucks;
GM Kodiac/TopKick 6500 chassis with Hydralic Brakes;
and many other chassis too numerous to list here, but you get the idea.

For those of you that have parked your rig because you are AFRAID to drive it - THIS IS YOUR FIX so you can get back on the road and FORGET ABOUT THE WORKHORSE RECALL FOREVER!!

What you need:

4ea. ACDelco Part#18FR1514 Re-Man Calipers 73mm $110ea. (plus core exchange)
4ea. Navistar (IHC) Part#2501845C91 Tie-Bar Kit w/Bolts $65 ea.

2ea. ACDelco Part#17D786M 73mm Brake Pad Sets $60 ea.
(The 73mm pads are thicker than the 66mm pads, but they are interchangeable if you want to use your old pads until they wear out.)

Total parts cost (excluding Brake Fluid) = $820

I do my own labor, so if you have a shop do it, you will have to add the shop's labor cost to the $820.

Notes: You can also use Re-Man Calipers from Bendix Part# SL55850 and CarQuest Part#18-8058, as well as many other suppliers. The 73mm Casting Number is 4153222 while the 66mm Casting Number is 4153269. These numbers are the same NO MATTER WHICH SUPPLIER you use. Also the 73mm calipers will have a large "73" cast into the back of the casting. See the photo titled "73mmCastNum.jpg".

Read the "BOSCH PIN SLIDE DISK BRAKE MANUAL" posted as a STICKY, by Driver, at the top of this forum. It contains all the necessary info for this change-out as well as all the bolt torque specifications and procedures. It is imperative that you read and understand it before doing the change-out. The maual page #46 gives all the different specifications for both the 66mm & 73mm Calipers - Please note the fluid capacity of the 73mm calipers is almost DOUBLE the 66mm capacity. Also note the exploded view of the calipers (fig.1, page 2) shows the installation of a SPLASH SHIELD, I did NOT have splash shields on my front brakes, but did have them on the rears. The instructions say the splash shields and ABS sensor brackets have to be installed on the opposite side of the anchor plate for the 73mm Calipers - I did NOT have to change my ABS brackets or the rear splash shields to accommodate the 73mm calipers. The Upper most Caliper Bolt on the rears was very close to my leaf springs when un-screwing it, but it did clear without having to remove the anchor plate or leaf spring U bolts to drop the axle for clearance. I had to use a 18mm boxed end wrench instead of a socket due to clearance, but it was not a problem. I have attached some photos of my rigs' front brake change-out and the rears are pretty much the same. My Chassis is a 2004 W-20 with 22.5 wheels built August 2003.

This change-out works with both the 19.5" and 22.5" wheels. Your ABS system is unaffected by the change-out and will operate as it always has.

Enjoy your new "FERRARI",,,errr I mean "WORKHORSE" brakes!

The 1st. photo is my original 66mm calipers, all the rest are the installation of the 73mm calipers and tie-bars.

[RottenRalph]

Help me understand. Are the 73mm made with the same materials (phenolic pistons) as the 66mm? If so, how would they be different other than the size? Would they also suffer the same moisture problem as the 66mm? If the pads are the same size, how could it stop better?

Thanks

[CoastieSCPO]

That's great information that Mutha posted and he is to be complimented for allowing all of us to share in the information. But Scott's rig is basically the same as mine and I have the same concern.

[max49]

Hmm, nice job Mutha. Seems like I've been reading on this forum for a long time, that it couldn't be done. (replacing 66MM calipers for the 73MM)
Why hasn't it been done before?

[JCM]

You would also get a larger braking surface. I wished I had known about this when I owned the rig. I will pass the info onto the new owner.
Thanks.

[Spoonman]

Originally Posted by max49

Hmm, nice job Mutha. Seems like I've been reading on this forum for a long time, that it couldn't be done. (replacing 66MM calipers for the 73MM)
Why hasn't it been done before?

I understood the same as you, wasn`t possible. Too late for me now, getting recall done then ADIOS!!!!
BTW,
Thanks Glenn for the great write-up and follow-up posts.

[Mutha]

Originally Posted by RottenRalph

Help me understand. Are the 73mm made with the same materials (phenolic pistons) as the 66mm? If so, how would they be different other than the size? Would they also suffer the same moisture problem as the 66mm? If the pads are the same size, how could it stop better?
Thanks

Are the 73mm made with the same materials (phenolic pistons) as the 66mm? If so, how would they be different other than the size? Would they also suffer the same moisture problem as the 66mm?

I do not know the composition of the pistons but they are larger in diameter and also almost twice as long as the 66mm so there is much more surface area to prevent water absorption to keep them from swelling like the 66mm. Also the caliper holds twice as much brake fluid so it would take much more moisture and substantially longer (more than 4 years) for the fluid to absorb enough water to contaminate the pistons if they are even made with the same phenolic formulation (and they may NOT be).

If the pads are the same size, how could it stop better?

The 73mm pads are much thicker (3/4" vs 1/2") so they should dissipate heat better and provide much longer wear. The diameter of the pistons is larger and therefore capable of much higher pressure. There is a formula that you can use to calculate hydraulic ram pressures, which basically says the larger the ram the more tons it will hold. It is something like geometric progression where a 1" diameter ram will hold 1 ton and 1 1/2" ram will hold 5 tons, etc..
Which would translate to a scenario something like "if you can stop a spinning disc in 30 seconds with a 1 ton ram you should be able to stop the same disc in 6 seconds with a 5 ton ram. Quicker stops mean less heat build up.

This is only my own postulations, as I am NOT an engineer, and what I think may be totally different than actual scientific facts, BUT if you will read pages 7, 8, and 9 of the Bosch Pin Slide Manual sticky at the top of this thread it explains the difference in the brake pads and the notes point out that the 66mm are rated to 23,500 GVWR while the 73mm are rated for vehicles OVER 26,000 GVWR and temperature exposure GREATER than 450 degrees for prolonged periods.

I cannot tell you the unbelievable difference in stopping power and "brake feel"

If you are truly afraid to drive your rig this is a must have modification for your own "peace of mind"!

Otherwise you might as well sell your Workhorse and buy a FORD that already has the 73mm brakes from the factory!

Best to all Glenn (AKA Mutha on the forums)

[Mutha]

Originally Posted by max49

Hmm, .........
Why hasn't it been done before?

Max, it has been done before, just not on the W-20 thru W-22 chassis.

Here is the Bendix Brake Catalogue:
Bendix - Application Look-up
1st click on "Front Calipers/Kits (or Rear Calipers/Kits)
2nd click on APPLICATION TYPE "Heavy Duty - On Highway"
3rd click on YEAR "2004"
4th click on MAKE "International"
5th click on MODEL "4700"
6th click on ENGINE "No Engine"

This will take you to all the uses for both the 66mm (sl55849) and the 73mm (sl55850). You can play around with it for FORD and Workhorse and Bluebird and others, etc., etc.

Glenn

[BellaBo]

Soooo, why didn't W/H opt for these as the new replacement brake calipers? It seems that they would be readily available and could avoid all the re- mfg. costs.

[CharlesOK]

I have a 2005 W22, regularly serviced, brake fluid changed last Spring and inspected by WH dealer, No problems reported, no overheating or cracking of the discs. Question is, after reviewing the IRL, it appears the 73MM was used on the WH chassis. Is it possible that some of us who have experienced no difficulty are already running the 73MM units and WH does not know which units have them, so they must recall all the units. If that were the case, is there a way to determine which we have??

[CharlesOK]

Seems like a $3,000 repair would beat the heck out of loosing the whole motorhome investment. All this carping on the Internet about how our motorhomes are undrivable is helping to destroy their market value. If You have aproblem with your brakes, GET THEM fixed and QUIT carping on the internet. It is a pain I'm sure, but thats enough $ to go about 6,000 miles at $2.75 per gallon. I don't get the beef. I have had a New MOHO in 1991 that had 3 transmissions in the first year. Reefers, AC units, come on, it all costs big bucks. The real Bitch is that WH will not do the work for FREE, therefore we must all suffer as a result of the whining of a few. Get over it, get it fixed and get on with it. Seems most folks have been reimbursed by WH even way after the warranty was over. Keep it up guys and we will all get rock botom trade-ins for our units. That way we can all share the grief.

[DriVer]

Originally Posted by Mutha

For those of you that have parked your rig because you are AFRAID to drive it - THIS IS YOUR FIX so you can get back on the road and FORGET ABOUT THE WORKHORSE RECALL FOREVER!!

Glen, You could install Rolls Royce Gold Plated calipers on a rig if they were available however there isn't anything that is going to clear the recall on our Class 6 vehicles other than to have the campaign cleared by using the new Bosch 66mm calipers from a WASC.

Rather than getting everyone's hopes up to go out of pocket for 73mm units, the recall will install new 66mm calipers with the new designs and piston material for free. "Out of pocket vs free" That's going to be a big decision.

Should we run 73 mm calipers all the way around? I thinks it's a little over kill for a vehicles in our weight rating. Even Ford uses 66mm calipers on the rear axle on its 26,000 GVWR chassis. The performance of my 66mm units is excellent in my opinion and I have not needed more brake like some shark fishermen needed a bigger boat.

In supplying chassis to OEMs, unlike Ford, Workhorse did not skimp when they specified that Arvin Meritor Quadraulic calipers be used for weight ratings of 24,000 or greater on all 4 wheel ends. Bosch brakes simply would not do.

As for me I have lots of time to go yet before I need to have my brakes done, but I will sign on to the "Next-Gen" caliper as soon as it becomes available.

Your observation about Bosch pin slide brakes used in commercial applications sustains what I have been saying for many years, They don't fail due to the heavy duty cycles imposed and repeated applications several dozens of times a day for 5 to 6 days a week.

You run a motorhome 66mm caliper like a truck and one would take even money that there wouldn't be many if any brake failures while using 66mm units.

I do agree 100% with your introductory comment ... "For those of you that have parked your rig because you are AFRAID to drive it - THIS IS YOUR FIX so you can get back on the road and FORGET"......

I replaced all my 66mm units 25 months ago and my motorhome is doing very well ... once the campaign on my vehicle is cleared I see no imperative to change my brakes over since mine stop well and they are very predictable and effective for relatively little force applied. The use of a TGB removed a great deal of need to constantly grab gears and apply brakes. In panic situation I can almost stand my 38 foot coach up on its nose because, the brakes are that good.

I would not contest that the 73mm brakes would not stop better, but to each his own.

[Max Hubrich]

Posted by Driver-
"Glen, You could install Rolls Royce Gold Plated calipers on a rig if they were available however there isn't anything that is going to clear the recall on our Class 6 vehicles other than to have the campaign cleared by using the new Bosch 66mm calipers from a WASC."

I could also make new Stainless Steel pistons (as pointed out in a previous thread), install them, and have the same feeling of security with my 66mm calipers. I have always stated that these are great brakes on my rig- Especially since I came from a P-30, tag axle setup. On that old rig, I had to set the "Brake Buddy" to a high sensitivity level to get decent braking pedal pressure and stopping ability- I loved the "tug" I got as the "Toad", a Saturn, brakes were alpplied. But nothing, short of a completed recall, will clear the rig for my ownership, or any subsequent buyer's ownership (a liability issue also exists). Then all our time, money and effort's will be for naught as our great "modified" brake systems are discarded as we return to, a new formula, 66mm phelonic piston calipers-.

I applaud Mutra for his efforts and I know he feels great driving his rig now- a heck of a job- He deserves an "Attaboy".

I change my brake fluid twice a year (probably an overkill), myself, knowing it was done completely and properly. But then I also, feel fairly secure driving down the highways. What worries me is the failures, as documented on this forum, that occurred almost immediately after other folks had changed, or had fluid changed by a repair facility.

This brings back memories. Some years ago I had an oil change and lube done by a national franchise on my company car (a Ford Crown Victoria). I had asked the manager before the work was done if a grease job was included. I asked this because I knew it hadn't been done properly before. He said "Yes". after the car was pulled out of the shop I turned the steering wheel full left and it was quite obvious the upper left ball joint zerk had not been serviced. I called the manager dude out and showed him the dirty zerk. Of course he pulled it back in and fixed the problem. I then wrote to their Corporte headquarters and they apoligized and sent me several free oil changes and lubes. Well, of course I went back to the same place each and every time. They never did get that zerk greased on the first try!! I just gave up.

I'll change the brake fluid again in about a month- just prior to our 6 months of being parked in Maine .

[idenphones]

I am not an expert by any means and I think that the idea of making the braking system bigger is a good idea. Bigger is better! At least that is what the wife says!

Anyhow, one thing comes to mind on this mod. The master cylinder is designed to put out so much fluid for a certain amount of stroke.

If the pistons in the calipers are 7 mm larger and there are 8 pistons that adds up to almost one additional piston over the stock setup.

In the manual for our toad, Ford says not to tap into the braking system as the masters cylinder is matched to the rest of the braking system.

So does this mod mean that the brake pedal needs to be pushed down farther to get the same results?

I don't imagine that it is going to make a big difference I am just curious.

What the heck, we need another topic to comment on anyhow!