Community Forums

"007" · 06-19-2012, 05:56 PM

Ramblin,You do gear down and take out of overdrive as someone has already suggested correct?
You may have to go down as far as 2nd or first depends on grade.

Ramblin · 06-19-2012, 08:18 PM

Quote:

Originally Posted by "007"

Ramblin,You do gear down and take out of overdrive as someone has already suggested correct?
You may have to go down as far as 2nd or first depends on grade.

Yes I do, and I've never had this sort of problem before. I may have been on the brakes more than usual this time, but I try not to touch the brakes at all unless I have to. Usually, Allison does a pretty good job holding the beast back. But when I do brake, I stab them pretty hard to bleed off the speed, then get off them trying to have at least 4:1 no brakes:brakes.

I have no explanation why this time I had a problem, when I've never had a problem before. I haul 10 ton loads of hay out of the mountains routinely with my dually and flatbed. I'm no newbie to dealing with grades.

I have never replaced the brake fluid in this coach, and I have no indication that the previous owner did either, other than he had the brake recall done, and I assume fresh fluid would have been part of that.

Oemtech · 06-19-2012, 08:49 PM

Quote:

Originally Posted by Ramblin

I have never replaced the brake fluid in this coach, and I have no indication that the previous owner did either, other than he had the brake recall done, and I assume fresh fluid would have been part of that.

Don't ASSUME anything.. I always figure they DID NOT do it and check. I flush/bleed my brakes fluid EVERY YEAR. Best $12 and 30 mins spent.

Here is a photo of 1 year old fluid compared to new.

DriVer · 06-20-2012, 06:18 AM

Quote:

Originally Posted by cb1000rider

The other thing you can do is move to a synthetic fluid.

As far as I know there has never been a mineral or petroleum based fluid used to make brake fluid. Any modern fluid that would be seen in the past 15 years on any vehicle in the US would be "synthetic" including Workhorse.

DriVer · 06-20-2012, 06:19 AM

Quote:

Originally Posted by Ramblin

Coming down the mountain last week, I was on the brakes a little more than usual. Nothing drastic.

I would ask the following, were you at all in compression? You didn't say.

DriVer · 06-20-2012, 06:23 AM

Quote:

Originally Posted by oemtech

Don't ASSUME anything.. I always figure they DID NOT do it and check. I flush/bleed my brakes fluid EVERY YEAR. Best $12 and 30 mins spent. Here is a photo of 1 year old fluid compared to new.

You can never show this picture too many times!

Change your brake fluid folks at least every 2 years and or 24,000 miles WCF.

You'll be glad that you did!

Please do not subscribe to the writings of people that would tell you that I've owned my car for over 20 years and never changed the fluid ... "Not Good!"

Ramblin · 06-20-2012, 06:41 AM

Quote:

Originally Posted by DriVer

I would ask the following, were you at all in compression? You didn't say.

I don't understand what 'in compression' means. Can you elaborate?

Also, do you know if replacing the brake fluid would be a standard part of the brake recall service?

dieselclacker · 06-20-2012, 07:14 AM

Ramblin,

While it probably should have been, replacing ALL the fluid in your brake system was not a standard part of the recent brake recall. Only enough fluid was supplied to replenish the amount lost during the process of replacing the calipers.

Ramblin · 06-20-2012, 07:21 AM

So, is the process of replacing the fluid in my W-22 similar to doing it on a standard vehicle? I know about the hydroboost system, but don't really know how it plays into the fluid change equasion.

DriVer · 06-20-2012, 03:01 PM

Quote:

Originally Posted by Ramblin

I don't understand what 'in compression' means. Can you elaborate?

Ramblin, "In Compression" means that you should be in a selected lower gear and allow the engine compression to assist in slowing the vehicle when coming off of a grade. The rule of thumb is that you should be in the same gear coming down off of a grade and was used going up the opposite grade (although that is variable and up to the experience of the driver)

This task is best accomplished using the Transmission Grade Brake (TGB) or an after market product if your vehicle was manufactured prior to model year 2005.

Driving a Class 6 vehicle, you "never" want to allow your service brakes to do all the braking. You need grab a gear and allow your equipment to help slow the descent of the vehicle. Yes you will want to stab the brakes to scrub energy off of the vehicle as your descend. You should also look for and maintain the safe descent speed for 18 wheel trucks will on grade. This is often posted and it could be as low as 45 MPH. Keeping your motorhome as a descent speed of 45 MPH will not hurt the engine in any way.

Just do not simply turn the OD switch to off. This does not provide enough compression. You need to initially pull the gear shift lever down to 3rd gear and allow it to run. If you are going to approach 45 MPH, just pump the brake pedal hard for about 1 to 2 seconds to scrub speed.

Quote:

Also, do you know if replacing the brake fluid would be a standard part of the brake recall service?

No it is unfortunately NOT part of the recall instructions. The Hydro-Max needs to be completely vacuumed and all the fluid at the wheel ends need to be bleed until clean (clear) fluid is observed coming from the bleeder (after the Hydro-Max booster tank is refilled).

DriVer · 06-20-2012, 03:04 PM

Quote:

Originally Posted by Ramblin

So, is the process of replacing the fluid in my W-22 similar to doing it on a standard vehicle? I know about the hydroboost system, but don't really know how it plays into the fluid change equation.

If you understand the process it is simple to accomplish. Just make sure that you do it properly and don't suck up air into the system and to keep the Hydro-Max tank full. Oemy has Speed-bleeders which will keep this from happening plus you can bleed with only 1 person.

Springer45 · 06-20-2012, 03:21 PM

With ABS and HydroBoost the bake flush is best done under continous presure, not the old pump and bleed process. You did not technically boil the brake fluid, you boiled the water in the brake lines, creating a void in the hydralic process. The only way to effectively replace all the fluid in your brake systme is by flushing using a power bleeder. Pump and dump leaves too much chance for air in the brake lines and ABS valves. Also all the suggestions pertaining to downshifting, or compression braking, are valid points used every day by experienced commercial drivers across the country.

DriVer · 06-20-2012, 03:27 PM

Quote:

Originally Posted by Springer45

The only way to effectively replace all the fluid in your brake system is by flushing using a power bleeder. Pump and dump leaves too much chance for air in the brake lines and ABS valves.

Workhorse service manuals will also recommend gravity bleeding, takes longer but t works.

Springer45 · 06-20-2012, 03:56 PM

Have not gravity bled one of these, but have done plenty of Yukons and Sierras. Must take the better part of a day to gravity feed a complete brake fluid change.