New noise

Topic: New noise (Read 668 times) previous topic - next topic

New noise

January 02, 2022, 04:52:22 pm

Good afternoon everyone,
I've been listening to a new noise that I should describe is a light hum.

It doesn't happen all the time and today when I was out I was making it occur as the coach was stopped after I hit the break but still moving up and down.
Got underneath the coach and saw this under the coach. It is coming from the long arm that goes to the steering box, I think the proper term is drag link.
I can't say that I'm hearing the noise when I turn the steering wheel.

Also would like to know if in the second and third photos that is what is known as the king pin.

Re: New noise

Reply #1 – January 02, 2022, 04:56:13 pm

No that's not a kingpin. From looking at your pictures it look like you have ball
joint suspension so you don't have kingpins.

Re: New noise

Reply #2 – January 02, 2022, 05:02:35 pm

Thanks Peter,
I looked in the parts manual but did not see anything written as a kingpin

Re: New noise

Reply #3 – January 02, 2022, 05:13:35 pm

#3 is the king pin.

It is labeled "Pin, steering knuckle"

Re: New noise

Reply #4 – January 02, 2022, 05:18:03 pm

Thanks Brett,
I'll have to get them checked and greased at MOT or FOT.

Re: New noise

Reply #5 – January 02, 2022, 05:29:52 pm

The greasy end looks like it could be angled. It should not be loose and recommend someone look at it while turning steering wheel back and forth. If it moves too much it could be too worn.

Steering pitman-arm moves drag-link, which moves tie-rod. Not sure which joint is in the photo.

Photo of axle end shows you have a solid axle like most with king pins at each end. The close-up photo is one of the two brake pad slide pins. As the pads wear, less of the slide pin sticks out, so your brake pads are not worn.

All front-end steering parts need grease.

Slide pins need cleaning and are not supposed to be lubed, but we spray and wipe off CorrosionX on slide pins after they are removed about every 3 years.

Of course, do not let anyone put chassis grease into Meritor brake grease-fittings, something that may be impossible to prevent if special care is not taken. Most techs have never seen Meritor disk brakes and almost correctly, without too much thinking, figure EVERY zerk grease fitting must immediately have chassis grease shot into them.

Re: New noise

Reply #6 – January 03, 2022, 12:49:04 pm

Barry,
The times that I have taken the coach to Cummins I specifically tell them to only do what i ask and DO NOT GREASE ANYTHING for the same reason.

Re: New noise

Reply #7 – January 03, 2022, 01:41:08 pm

Frank, in my experience, the more trained & experienced the tech, the more likely they will put grease in every zerk grease fitting. How could they do different with their carrying to do the best job.

We put small cable ties around each Meritor zerk and leave 'tail' of cable tie hanging. It give me something to identify and usually someone will ask why they have cable tie.

Understand that some places may better follow direction, but hard to trust it 100%.

I see you are telling them to not grease any fitting... That should work.

Re: New noise

Reply #8 – January 03, 2022, 01:48:54 pm

Nobody has mentioned it but in the first picture the rubber boot on the ball joint is gone,may be time to replace.

Re: New noise

Reply #9 – January 03, 2022, 01:49:26 pm

Actually, if there is a chance you will allow a "less than Foretravel savvy tech" to grease the chassis, best answer is to remove the grease zirks on the disk brakes and install a dead plug. Regular grease, particularly if not properly bled can cost you several coach bucks.

Re: New noise

Reply #10 – January 03, 2022, 01:52:05 pm

Quote from: John44 – January 03, 2022, 01:48:54 pm

Nobody has mentioned it but in the first picture the rubber boot on the ball joint is gone,may be time to replace.

Another school of thought is to just grease it more frequently and only replace when there is mechanical play.

Said another way the rubber boot life expectancy is far less than the joint itself.

Easy to check for play-- no tools and only takes a minute or two.

Re: New noise

Reply #11 – January 03, 2022, 02:19:04 pm

So just how often should the 2 zerks on the caliper be greased. We just had our brakes rebuilt for the third time.

First time.. right after purchase ( local truck shop )

Second time is on me. At foretravel but without the joystick on the retarder. Just couldn't seeem to get the whole RPM
Speed brake thing down. In my defense I don't see how you do a long 6% grade using the 3 stage retarder brake activation
Without heating up the brakes. Maybe 30 MPH would better than 45 and 3rd gear rather than 4th.. but
Got the JStick now so downgrades are working much better.

This last time was most likely because I haven't been servicing the brake pins I think. The brake pin springs help but those pins still need to be cleaned annually or bi-annually apparently.

Re: New noise

Reply #12 – January 03, 2022, 02:26:40 pm

Quote from: Bob & Sue – January 03, 2022, 02:19:04 pm

So just how often should the 2 zerks on the caliper be greased. We just had our brakes rebuilt for the third time.

In my defense I don't see how you do a long 6% grade using the 3 stage retarder brake activation
Without heating up the brakes. Maybe 30 MPH would better than 45 and 3rd gear rather than 4th.. but

I suspect a part of the how often to grease depends on their use (actually, there non-use) and also if operated on salted roads, etc. Except in harsh conditions like above, the recommendation I have seen is once in the life of the pads. For an RV application, perhaps every 2-3 years is more reasonable, as brake pads have a very long life on coaches equipped with retarders.

I am also a fan of the springs that help in pad retraction.

The correct speed and gear for a long descent is one that does two things: keeps speed in equilibrium AND doesn't severely overheat the transmission fluid. Gear down so your engine is toward the higher end of its RPM range (water pump turning faster) and use the least retarder setting to keep your speed from increasing.

If speed increasing and/or transmission temps getting too high and/or you are at the top of your engine's RPM range in that gear, use the brake pedal firmly and long enough to drop to the next lower gear.

As a general rule, you will be faster than a loaded 18 wheeler and slower than an empty one. Keeping up with car traffic-- you are going WAY TOO FAST!

Re: New noise

Reply #13 – January 03, 2022, 02:43:08 pm

On our trips last year I learned how to keep the retarder temp. down on different grades. What surprised me was how much wind resistance helped. Keeping between 55 and 60 let me use less retarder on grades because of the wind resistance. It takes some experimenting to get the different grades and gears along with the retarder to keep the temps. down.

Re: New noise

Reply #14 – January 03, 2022, 02:45:12 pm

Quote from: wolfe10 – January 03, 2022, 02:26:40 pm

As a general rule, you will be faster than a loaded 18 wheeler and slower than an empty one. Keeping up with car traffic-- you are going WAY TOO FAST!

No problem there. The only place where I keep up with traffic is in town. Or maybe California where trucks are supposed to go 55.

So down the mountain too fast,, brake down to next lowest gear with minimal retardation. Got it.

Re: New noise

Reply #15 – January 03, 2022, 02:47:28 pm

Yes, you need to balance trans temp/engine RPM/speed.

There is a learning curve.

The only wrong answer is to ASSUME you can put it in D and just drive!

Re: New noise

Reply #16 – January 03, 2022, 03:17:48 pm

Quote

We put small cable ties around each Meritor zerk and leave 'tail' of cable tie hanging. It give me something to identify and usually someone will ask why they have cable tie.

That sounds like a good idea. Where are these grease zerk's that are not supposed to get grease?

Re: New noise

Reply #17 – January 03, 2022, 03:33:36 pm

Quote from: WS6_Keith – January 03, 2022, 03:17:48 pm

Where are these grease zerk's that are not supposed to get grease?

Keith,

It isn't that they are not supposed to get grease, the thing is if you grease the caliper they have to be properly purged after greasing. The location and proper procedure is in the 4M ADB brake book. Look/review section 13.
https://www.foreforums.com/MGalleryItem.php?id=1701

Mike

Re: New noise

Reply #18 – January 03, 2022, 03:35:47 pm

Quote from: Pamela & Mike – January 03, 2022, 03:33:36 pm

Keith,

It isn't that they are not supposed to get grease, the thing is if you grease the caliper they have to be properly purged after greasing. The location and proper procedure is in the 4M ADB brake book.
https://www.foreforums.com/MGalleryItem.php?id=1701

Mike

Yup, proper high-temp grease AND proper purge procedure. If not properly purged, the pads will not retract properly.

Re: New noise

Reply #19 – January 03, 2022, 03:47:44 pm

In response to a Forum personal message where I cannot attach files:

Attached is where the brake grease fittings are located. I don't have photos and hopefully the diagram will help.

Re: New noise

Reply #20 – January 03, 2022, 04:04:11 pm

This is great info! Saved the grease procedure and the entire brake manual. Thanks guys!

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