Right Front Brake Pads Dragging

Topic: Right Front Brake Pads Dragging (Read 3350 times) previous topic - next topic

Re: Right Front Brake Pads Dragging

Reply #25 – December 11, 2016, 08:41:13 pm

Here is the slack adjuster tool.

http://www.tooldiscounter.com/ItemDisplay.cfm?lookup=KAS4651&source=froogle&kw=KAS4651&gclid=CjwKEAiAj7TCBRCp2Z22ue-zrj4SJACG7SBEIOyUtYEosI7RqHcC_QTrQMU2gc0ij6QnhKHOLV1KGRoCCpHw_wcB

Re: Right Front Brake Pads Dragging

Reply #26 – December 11, 2016, 08:44:26 pm

Quote from: its toby – December 11, 2016, 08:30:30 pm

Please if you don't know what you are doing be careful with this.

I understand and concur with your concern, Derek. I only posted this procedure as a emergency action to enable members with a locked up brake to get their coach off the side of the road, without resorting to calling a mechanic or a tow truck.

If this emergency procedure IS used, the coach should be driven (slowly and carefully) directly to a qualified service facility, where it should be inspected by a experienced technician to determine the cause of the malfunction.

The proper adjustment of the brake caliper and slack adjuster is clearly explained in the manual I linked above.

Re: Right Front Brake Pads Dragging

Reply #27 – December 11, 2016, 08:48:55 pm

Is there a reason that a person would not want to degrease and wash off the dirt and grease residue in the pictures ?? ( sorry, another dumb question perhaps ).

Re: Right Front Brake Pads Dragging

Reply #28 – December 11, 2016, 09:00:57 pm

Quote from: Bob & Sue – December 11, 2016, 08:48:55 pm

Is there a reason that a person would not want to degrease and wash off the dirt and grease residue in the pictures ??

Robert,

Again, not a dumb question. I share your feeling that wiping off the excess grease with a rag would be desirable. However, in my experience very few "grease monkeys" (OOPS - I mean Professional Chassis Lubrication Technicians) worry about all those globs of goop, assuming I suppose that it will eventually fall off or blow off.

When we finally get back to home base, you can be sure I will be under the coach doing a little "housekeeping".

Re: Right Front Brake Pads Dragging

Reply #29 – December 11, 2016, 09:04:43 pm

Cleaning excess grease off is not a bad thing however going crazy with heavy cleaners and brake clean can cause issues. The release can become seized also at the end of the slack there are two pins that go through the clevis and the slack to transmit the force from the chamber. If these pins do not rotate freely when not under braking force they can cause the brakes to not release correctly and can either wear out the pins or the clevis or the slack itself.

Re: Right Front Brake Pads Dragging

Reply #30 – December 12, 2016, 07:04:37 pm

Chuck,
I'm back on the forum again for a bit, and am sorry to hear about your problems. I hope MOT does what is right by you and am glad you were able to make it back to NAC safe and sound.
Take care and happy landings!
Len

Re: Right Front Brake Pads Dragging

Reply #31 – December 12, 2016, 08:34:35 pm

Update:

Well, today was a mixed bag. MOT had us come to the shop first thing - got us right in a bay. The techs pulled the RF wheel and inspected the brakes. The first thing they found was the bearing "play" was a bit too tight. On that corner they had replaced the inner oil seal last Wed., so the whole spindle assembly had been apart and back together. They also determined that the brake caliper did not have sufficient grease due to a big air bubble trapped inside (?). So anyway, they reset the bearing clearance (used a dial indicator), greased and purged the caliper, greased the slack adjuster, adjusted the slack with the correct yellow template, and buttoned everything back up.

I went out for a long test ride with Kieth (Risch) He drove at varied speeds, exercised the brakes, and stopped several times to check the brake rotor temps with a infrared thermometer. He said everything felt OK to him, and the temp checks looked normal. He did ask me if our wheels had ever been balanced, and I said no because the coach had always felt extremely smooth to me at all speeds. Otherwise, nothing notable was found.

This work took about 3 hours, and of course there was no charge. Since it was too late to leave for home, we decided to take the coach for a extended drive around the loop and up and down Hwy 59 north of town. The coach felt pretty good as far as braking, but I soon became aware of a pronounced "shimmy" in the steering wheel. This occurred between 60 and 65 mph, and seemed to "come and go". Since the coach was dead smooth with zero steering problems before this work was done, I decided the shimmy was not a good sign. Got back to the FOT parking lot, and called Kieth. I told him what I felt in the steering, and he agreed it was not "right". He said they had checked the brake rotor runout, and it did not appear to be warped, but he wanted to take another look at it.

Bottom line - we're going back to MOT (again) first thing tomorrow and let them have another look. I'm not leaving NAC until I'm convinced everything is correct. So far, MOT has been willing to put me ahead of other service customers, and is trying to work with me. Hopefully, tomorrow will be our last trip over to their shop, and we can soon head for home.

Will report again tomorrow!

Re: Right Front Brake Pads Dragging

Reply #32 – December 12, 2016, 08:43:21 pm

My guess is the rotor got warped. When you drive it and lightly touch the brake pedal it would be more pronounced. Also after getting warmed up the steering would start to pulse.

Re: Right Front Brake Pads Dragging

Reply #33 – December 12, 2016, 08:45:48 pm

Quote from: craneman – December 12, 2016, 08:43:21 pm

Also after getting warmed up the steering would start to pulse.

That is exactly what I felt - the "pulsing" in the steering wheel. But I did not detect any odd feel through the brakes under light application.

Re: Right Front Brake Pads Dragging

Reply #34 – December 12, 2016, 10:09:42 pm

On the side that got hot, I would have expected new rotor and pads. Both would be suspect after being exposed to that heat. Did they re use pads? Definitely would ask for new rotor and pad on that wheel at no charge

Re: Right Front Brake Pads Dragging

Reply #35 – December 12, 2016, 10:21:30 pm

They did install new pads. We'll see about the rotor tomorrow...

Re: Right Front Brake Pads Dragging

Reply #36 – December 12, 2016, 11:50:54 pm

Brake rotor should be checked for cracks, but are pretty durable, from what I've seen from your post they checked the run-out with a dial indicator to indicate a warped rotor, but it won't account for improper torque as they tighten lugs. Road racer's used to heat up the rotors until they were brilliant pumpkin orange at the end of every straight. Glazed pads or rotors can be hit with a scotch brite pad and rebedded. Wish for a positive outcome.

Re: Right Front Brake Pads Dragging

Reply #37 – December 13, 2016, 02:12:49 am

Coming through Colorado in oct I used our brakes hard without the retarder to keep the temp rise down in along grade.

Steering wheel shimmied. Turned on retarder and with lighter use no brake shimmy.

Three thousand miles later I noticed the coach pulling to the left.

Took it in and the cummins shop said I had warped front rotors with the felt one being worse.

They said they were turnable so that's where we are today.

And I had front seal leaks.

Re: Right Front Brake Pads Dragging

Reply #38 – December 13, 2016, 08:43:35 am

Quote from: Chuck & Jeannie – December 12, 2016, 10:21:30 pm

They did install new pads. We'll see about the rotor tomorrow...

I would not ASSUME the rotor is bad (or good). Inspect it, looking particularly for cracks and run-out.

Re: Right Front Brake Pads Dragging

Reply #39 – December 13, 2016, 09:30:22 am

My rotor was also brilliant pumpkin red (twice) when I had the slack adjustor issue, which is why Parliament in St. Pete suggested to change it out - not sure what they were worried about, but it was on their dime, not mine, and they wanted to change it to be safe. I forget what the IR meter said when I scanned the rotor when I stopped, but it was a scary high number -

My situation leading up to the initial brake repair was - no issue with Brake operation, but one pad was excessively worn on passenger rear - probably because of light dragging over time in the past due to slow caliper release, but not enough to make the rotor smell or turn red.

Took in to shop - TN RV did both rear brakes. I drove 60 miles, turned around and came back to TN RV with hot smelly brakes. They "adjusted" the brakes, still hot smelling - but they swore that would go away. Drove to Parliament in St Pete. - they redid the brakes, TN RV paid them to do the job (Good customer service on their part). Stayed Winter in FL.

I drove to IL and back to FL, and the brakes stuck twice on that trip - both times I stopped on side of Expressway to let cool down. I was able to get rotor to release by pumping brake hard while stopped, and it didn't stick again. RED hot both times. Got back to Parliament, they scratched their heads and brought in a mechanic from outside, The outside mechanic diagnosed the issue as a bad slack adjuster, ordered new slack adjuster, rotor and pads. Put it back together, not problems since.

All said, the inconvenience factor was pretty high, but both Tenn RV and Parliament made good on the costs, so I walked away OK with how it all turned out, and no hard feelings.

Any metals guys on the Forum with an answer as to if rotor is compromised in some fashion due to excessive heat?

Re: Right Front Brake Pads Dragging

Reply #40 – December 13, 2016, 10:23:27 am

Would look for cracks on rotor and see how deep/bad they are,the only thing to cause the cracks would be excessive heat,this
causes metal to become brittle.

On the slack adjuster,never took one apart but I'm assuming yours just wore out.Unless you had a higher priced IR gun you
probably went past the range on your rotor.

Looks like with all the trouble posters have had with brakes lately my advice would be,road test and road test.

Re: Right Front Brake Pads Dragging

Reply #41 – December 13, 2016, 10:54:42 am

I try to remember to stomp on the brakes a couple times before we leave out. It seems to help keep the brakes "limbered up"
Len

Re: Right Front Brake Pads Dragging

Reply #42 – December 13, 2016, 05:40:37 pm

Update.

Spent another morning at MOT, and I can finally report SUCCESS! The steering is now restored to it's former glory, and I am a happy camper.

To continue my tale...we got to MOT at 07:45 and were immediately put into a service bay. Techs pulled the RF wheel off (again). Went through a exhaustive check of the rotor, including runout, concentricity and thickness. Everything checked out OK. Put the wheel back on, but rotated it 180 degrees from original position ( on the wheel studs). Then I went for another test drive with Kieth Risch. He could still feel the pulsation in the steering wheel. Back to the shop, again removed the wheel. Kieth said he wanted to get the tire and wheel checked, so he personally ran it over the Herman Power Tire. They inspected the tire, then put it on their spin balance machine, and found it was unbalanced - so they corrected that. Back at MOT, wheel was reinstalled, and we went for another test drive. This time we had success. The coach was perfectly smooth through the steering wheel at all speeds, and stops GREAT!

Nobody at Mot can really explain why the pulsation appeared in the steering, and how it was related to our "hot brake" incident. Our wheels have always felt well-balanced to me, yet after the brake locked up, the wheel was not balanced. We checked to see if some tape-weights had perhaps fallen off the back side of the wheel (from the heat), but that wheel did not have any balance weights attached before the incident. It is a real head-scratcher, for sure. Whatever the reason, balancing the wheel fixed it.

To summarize my impression about this whole sequence of events, the original problem was probably due to incomplete purging of the brake caliper. The young tech apparently followed the proper purging procedure, but did not get the desired result. When we left NAC headed for home, the RF brake caliper stuck after about an hour on the road. The other 3 brakes were (and are) fine, so this was a freak occurrence which is not likely to be repeated. I am sure the young tech will get some retraining on the purging routine. MOT addressed the situation with a immediate positive response, putting me ahead of other customers, and doing their best to diagnose and correct the malfunction. While the actual correction process took longer than expected, due in part to the mysterious steering wheel pulsation, in the end they were able to finish the job to my complete and total satisfaction. They did not charge me anything for the (almost) one full day of extra shop time, and went out of their way to make Jeannie and Bella and I as comfortable as possible while we waited.

I bear no ill will against MOT, and will continue to recommend them to Forum members. I personally consider this a valuable learning experience. I now know a great deal more about the braking system on our coach, and that is a good thing. I now understand the importance of monitoring braking performance and wheel temps, especially after a major brake service job. If I had taken the simple step of stopping several times to check brake/rotor temps when we first hit the road, I could have probably detected the problem before it became a "emergency". You can be sure I will be more proactive in this regard in the future.

Bottom line: STUFF HAPPENS. MOT stepped up and did what was right. Can't ask for more than that!

Re: Right Front Brake Pads Dragging

Reply #43 – December 13, 2016, 07:09:07 pm

Nice outcome for both sides.
Regarding the balance of front tires, I had that done when put the new ones on and the rears too. Yes the stick on weights kinda look bad but I like the fact they are balanced more than the looks.
JohnH

Re: Right Front Brake Pads Dragging

Reply #44 – December 13, 2016, 07:27:29 pm

Chuck,
How hot was your tire?
Don't know if these tires have it but sometimes a thin rubber weight patch is factory installed inside so the manufacture can ship a well balanced tire.
Some aircraft tires are balanced this way.
If a tire gets too warm those weight patches can come off and relocate and it will indeed change the balance. Only way to tell is demount the tire and look inside.
I wouldn't do that unless that tire mysteriously goes out of balance again later indicating that weight has moved again.

Re: Right Front Brake Pads Dragging

Reply #45 – December 13, 2016, 08:19:08 pm

Quote from: John Duld – December 13, 2016, 07:27:29 pm

How hot was your tire?

Don't know! I wish I'd had the presence of mind to pull out my "temp gun" and check the wheel and tire...but I didn't.

In my defense, I seriously thought something was on fire in the wheel well, and that kinda distracted me.

Re: Right Front Brake Pads Dragging

Reply #46 – December 13, 2016, 08:53:49 pm

Chuck,
Hopefully all is well but I think I would look the tire over at the end of the next few travel days just looking for any sign of a side wall separation. A tread seperation I think you would hear and feel as you drive.

Re: Right Front Brake Pads Dragging

Reply #47 – December 13, 2016, 11:20:30 pm

And as the sun sets on Coach Buck City another happy camper hits the trail for home.

Glad to hear it worked out for you guys!
Merry Christmas

Re: Right Front Brake Pads Dragging

Reply #48 – December 14, 2016, 01:00:23 pm

We always use the retarder and seeing temps for a short time over 250-300 degrees is acceptable to us and our Transynd fluid. We would never rely on brakes only as they are our emergency backup in case retarder does not do it for us. And now Bob & Susan have found another reason to use the retarder.

Re: Right Front Brake Pads Dragging

Reply #49 – December 14, 2016, 02:24:58 pm

I use the retarder quite a bit. Especially in traffic as the brakes cool off after a bit if warmed up.

Had a panic stop last trip. Brakes fairly cold. Retarder on.

Stopped well. Stops very well if the brakes are warmed up and deglazed without the retarder.

Like a race car with warmed up brakes and the retarder as most here know very well.

Two different owners of 97 m11 cummins have reported different thermostat setup's.

One with and one without a restrictor plate to ensure more coolant to the trans cooler.

Love to see what, if any, the trans temp differences might be with or without the restrictor.

Shop is redoing my warped front rotors and had one wheel seal leaking so it's being done.

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