Helper springs on Meritor disc brakes

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Helper springs on Meritor disc brakes

September 20, 2012, 09:09:40 pm

All,

Here are some pictures of the Meritor disc brake helper springs and some installation and greasing tips. If you have the brakes inspected and the slide pins cleaned you should have the helper springs installed. I cannot imagine much increased cost beyond the cost of the spring kit (about $18.00) at the time of pin cleaning because the pins have to come out to be cleaned and the springs just slide in. The spring kit (Meritor P/N KIT15018) contains the two springs required, one for the upper pin and one for the lower pin. The thread in the end of the slide pin is a 3/8 -16 and using a 3/8 bolt makes it easy to pull pin and hold it while cleaning it. The maintenance manual allows light lubrication of the slide pins after inspection and cleaning;

Page 40 Meritor Maintenance Manual 4M (Revised 04-05)

"18. Clean, inspect and measure the slide pins and bushings. Refer to Section 12 for information about cleaning the brake components.
A. Clean the slide pin. Remove any paint or other material from the pin. Replace the pin when you find burrs, nicks, corrosion, or other damage. Lubricate the slide pins lightly with WD-40, Spray CRC or a similar product."

I use a silicone spray that leaves a dry film.

There has been a lot of talk about not greasing the calipers too much. I would say the real issue is improper greasing. You could grease the calipers once a month if you wanted to. You just have to do it correctly. Just follow the instructions in the maintenance manual. Of course it is not necessary to grease that often and it has been 4 years (about 15K miles) since my brakes were inspected and greased. Upon regreasing the old grease looked ok but the pins had some residue on them. At one point I had some brake squeaking and I sprayed some of the aforementioned silicone spray on the pins and that seemed to take care of the squeak. The residue on the pins looked like it had been on there for a while and not accumulated as a result of the silicone spray. I took the pins out, cleaned and inspected them and reinstalled with the helper springs and greased the calipers. I now have a baseline for the condition of all four of my brakes and have formulated a maintenance schedule for them based on their current condition and depending on what mileage I put on.

GREASING TIP; Slack adjustment pawl may be locked open with a small ignition wrench, the one seen in the pic is an 11/32 about .090 thick.

Hope this helps.
Good luck,
Rick

Re: Helper springs on Meritor disc brakes

Reply #1 – September 20, 2012, 09:18:55 pm

Great write-up, Rick. Can you educate/remind us on the need for the helper springs? I don't recall a prior thread on them so I'm trying to connect the dots.

Tnx,

Michelle

Re: Helper springs on Meritor disc brakes

Reply #2 – September 21, 2012, 06:18:35 am

I had them put on as well. There is a soft recall for our brakes and Meritor recommends the helper springs. It prevents the brake from dragging. I had a front brake drag a bit and that started the whole process. I know a friend had one drag on the way to a rally too. I have not had any issues since the helper springs were installed. THey are recommended for the front wheels by Meritor.

Re: Helper springs on Meritor disc brakes

Reply #3 – September 21, 2012, 08:27:11 am

Quote from: Michelle – September 20, 2012, 09:18:55 pm

Great write-up, Rick. Can you educate/remind us on the need for the helper springs? I don't recall a prior thread on them so I'm trying to connect the dots.

Tnx,

Michelle

Michelle,
John has mentioned it above but there was a lot of info posted on the Yahoo forum and the cautions stuck with me. I did a search on disc brake springs here and came up with this

Meritor Disc Brakes Maint

There is more, so if wanted one can do a search and read. As I mentioned, for what should be a small additional charge while having brake pins cleaned, adding the springs would be a worthwhile addition. At least ask the service people for a price and make your decision.

In my case I was just doing routine maintenance and inspection and added them. I also discovered that whoever worked on my rear brakes last had removed the purge/relief valve and put a regular grease fitting in it's place. I bought new valves and put them in. My guess is that that relief valve is there to bleed off grease in a high temperature event or just as a minimal safety valve for an improperly greased/purged caliper.

Keeping disc brake slide pins (and/or rails) clean are a must for disc brakes to work properly. Most automobile applications have those pins in a totally sealed tube design (sometimes the seal fails and the pins rust up and stick), some calipers ride on exposed rails, dirt and grime accumulate on them and make the brakes drag or actuate one side only. The Meritor pins we have are exposed and therefore subject to the environment you expose them to, hence my emphasis on keeping them clean. If you drive on roads treated for ice the corrosive elements (salt, liquid calcium chloride, sand) can get between the bushing and pins to cause pitting that will then capture dirt and grime and cause the caliper to stick/drag/hangup. Liquid calcium chloride is also used to control dust on unpaved roads and construction areas, so if those environments are regularly encountered you should keep it in your mind to include detailed slide pin maintenance on your punch list. My guess is that if you ask maintenance people to look at the brakes that is exactly what they will do, just look, and just at the pads and if they look good then all else must be good.

Just my opinion,
Good luck,
Rick

Re: Helper springs on Meritor disc brakes

Reply #4 – September 21, 2012, 09:21:19 am

Quote from: John S – September 21, 2012, 06:18:35 am

I had them put on as well. There is a soft recall for our brakes and Meritor recommends the helper springs. It prevents the brake from dragging.

Quote from: Rick – September 21, 2012, 08:27:11 am

John has mentioned it above but there was a lot of info posted on the Yahoo forum and the cautions stuck with me.

for what should be a small additional charge while having brake pins cleaned, adding the springs would be a worthwhile addition.

Thanks John and Rick. We do have our brakes cleaned and adjusted as part of our annual service and I will add the helper springs to list of things for the next one.

Michelle

Re: Helper springs on Meritor disc brakes

Reply #5 – September 21, 2012, 12:40:36 pm

There was quite a bit of discussion about these Meritor helper springs in the past because some folks have found brake disk pads very heavily worn on one end because only one slide pin was stuck. This was generally on the rear brakes.

I had driver side front brake stay engaged sufficiently to become smoking hot. I could smell the burning brake pads from the driver seat. I stopped and pounded on the caliper, which cleared it so that I could get home. At home, I cleaned all the brake caliper pins in place using cut strips of plastic scrub cloth. Awkward but doable. Calipers have not stuck for last two years because I clean them annually without dismantling.
I will order eight helper springs when I travel to California at Halloween. Anyone know who to order them from online?

Great pictures and how to instructions in previous post, thanks for that.

Re: Helper springs on Meritor disc brakes

Reply #6 – September 21, 2012, 08:09:35 pm

P.W.
Several weeks ago I bought from here

KIT15018-MERITOR-KIT-SPRING

They have gone from $17.66 per kit to $20.08 today, I just checked. They did ship on time and it was a painless transaction. Maybe somebody has a better price now.
Good luck,
Rick

Re: Helper springs on Meritor disc brakes

Reply #7 – September 22, 2012, 10:01:14 am

I got mine from meritor.

Re: Helper springs on Meritor disc brakes

Reply #8 – September 22, 2012, 06:55:47 pm

How many are needed?

Re: Helper springs on Meritor disc brakes

Reply #9 – September 22, 2012, 07:02:32 pm

Bob,
In each kit there are two springs and that will do 1 caliper, one for top pin, one for bott pin. So for a 2 axle coach you need 4 kits. I do not know what there are for brakes on a tag axle.
Good luck,
Rick

Re: Helper springs on Meritor disc brakes

Reply #10 – September 27, 2012, 03:54:10 pm

I'll bet this would have helped prevent the toasted pad and rotor I had to replace at FOT earlier this year. I am surprised Wayne did not recommend these when I asked about the cause (he had no idea what might have caused this failure). On my way back to Oregon the same rotor/pad got hot enough to smoke. Service in Grants Pass, OR lubed the pins and I have not had any further problems. I will plan to have these springs installed at next service.
Thanks for the heads up on this!

Re: Helper springs on Meritor disc brakes

Reply #11 – November 08, 2012, 06:33:14 pm

Ours arrived yesterday; we used FinditParts and they were drop-shipped from Meritor in just a few days. Do a coupon code search - we saved 5% as new customers.

FOT also has them - higher cost but not all the way to MSRP. We would have bought from FOT last week but they were down to 6 kits and we knew they needed 4 of them for Harvey N's coach (we asked first and they hadn't pulled parts for Harvey's work order yet). Billy Jack said they had more stock on the way but we were leaving Nac before the shipment arrived.

Michelle

Re: Helper springs on Meritor disc brakes

Reply #12 – November 08, 2012, 07:59:37 pm

Ha! When I was working up my work order with Billy Jack I mentioned the Meritor helper springs. He said you know you don't really need them. I said yeah but to me it's cheap insurance so why not? I told him I heard about it on ForeForums. He immediately picked up the phone, called parts and told them to order a dozen more sets.

They did find my front discs were worn and the leading edge of the pad had some small chips in it. Not sure what would cause that. Had them replace the pads.

see ya
ken

Re: Helper springs on Meritor disc brakes

Reply #13 – November 08, 2012, 09:55:15 pm

Bought enough to do my 97 and my mechanic did the front seals and installed the springs.

I did have the left front drag some in may. Enough to smell it in the coach. Hit the brakes and it released.

Re: Helper springs on Meritor disc brakes

Reply #14 – November 09, 2012, 06:55:31 am

My opinion is simply the helper springs are a great idea for those that either do not want to keep serviced or do not know how to properly inspect and maintain the brake system.
I would also be as happy with the old standard S Cam, shoes & drum that is the normal / common setup on most truck and bus systems.
Coupled with the Retarder, both systems are great, however the disc system takes more money & time to keep up to snuff.
MHO
Dave M

Re: Helper springs on Meritor disc brakes

Reply #15 – November 09, 2012, 10:32:53 pm

So I can I assume we need 6 kits with a tag axle coach??

(This may explain why I had to replace one pad set on the DS tag a few years ago)

Re: Helper springs on Meritor disc brakes

Reply #16 – December 11, 2012, 12:42:00 am

Slide pin corrosion. This seems covered well in the prior entries to this thread but due to the safety issue, I want to revisit the potential danger aspect due to a recent experience. 1. A friend with a new to him coach drove with the retarder "off" and some shudder when applying the brakes without the retarder's help. He learned that corrosion on pins was so severe that the wheel could not be turned by hand (disk would not release), only the diesel engine pushing made the wheel turn. His attention to this averted a possible accident or greater repairs. 2. These pins are not normally inspected in annual maintenance per one major service organization. You need to ask for that. Few ask.

A service technician told me that he had a frozen brake get so hot that it ruined the wheel. For safety, I will follow the option of having the wheels pulled to check and the helper springs sound a good addition. Send PM if want more photos of the pin mechanism.

Re: Helper springs on Meritor disc brakes

Reply #17 – December 11, 2012, 01:27:53 am

Hi Mike,
Can I see more pictures of the slide pins?
Thanks,
Raymond

Re: Helper springs on Meritor disc brakes

Reply #18 – December 11, 2012, 08:15:04 am

Quote from: Raymond Jordan – December 11, 2012, 01:27:53 am

Hi Mike,
Can I see more pictures of the slide pins?
Thanks,
Raymond

Here are some before and after cleaning on my coach.

Re: Helper springs on Meritor disc brakes

Reply #19 – December 11, 2012, 09:17:39 am

Raymond, got your pm and attached is a photo of just the corroded pin, Rick has given you a good photo of where they go, fit together. This shows the corrosion and if you run you hand along it you feel ridges where the destruction is easily felt as well as seen. I then put on a rather poor picture of "where it goes" from a larger, outside the axle, view. You will see the hole above the wheel and other part to the upper right of the wheel. The technician did quite a bit of work to clean up the assembly that was not replaced.

I think it was Ken H that told me that there is a way to help keep these clean or detect a problem, I hope he weighs in. Beyond that of course are the references that folks made to cleaning these yourself, or at least trying.

I hope Don will post what he felt driving and the episode or cause that led to having this whole thing taken apart.

mike

Re: Helper springs on Meritor disc brakes

Reply #20 – December 11, 2012, 10:05:19 am

Do the springs go in the gap closest to the inside where the pin sticks out or the other side?

These two photos from prevous postings seem to show springs installed toward center of coach and toward the outside of coach.

Where do the springs go?

Re: Helper springs on Meritor disc brakes

Reply #21 – December 11, 2012, 10:16:43 am

Barry,

Springs goes on OUTBOARD side of the Torque Plate with larger end toward the Torque Plate.

Re: Helper springs on Meritor disc brakes

Reply #22 – December 11, 2012, 10:37:39 am

Brett,

Is it correct that the Torque Plate is the center casting that supports the rotor?

And that "right+rear...2" photo has the spring correctly installed?

And that "brake help...installed" photo has the spring on the incorrect side?

Does the spring 'help' the piston side of the caliper to move away / relax from the rotor?

But it seems the spring will put mild pressure on the caliper to further drag the brake pad not on the piston side.
Putting a optional spring in the mix seems to put one pad further from rotor, which has to put the other pad closer to the rotor?

Re: Helper springs on Meritor disc brakes

Reply #23 – December 11, 2012, 10:49:20 am

REPLY IN SOLID LETTER CAPS.

Quote from: Barry & Cindy – December 11, 2012, 10:37:39 am

Brett,

Is it correct that the Torque Plate is the center casting that supports the rotor?

YES

Quote

And that "right+rear...2" photo has the spring correctly installed?

YES

Quote

And that "brake help...installed" photo has the spring on the incorrect side?

HARD TO GET A PERSPECTIVE ON THAT PHOTO, BUT THE SLIDE PIN SHOULD BE (AND IS) STICKING OUT THE INBOARD SIDE-- SO, I BELIEVE IT IS ALSO CORRECT.

Quote

Does the spring 'help' the piston side of the caliper to move away / relax from the rotor?

NO, IT PUSHES THE "LAZY"/OUTBOARD SIDE AWAY FROM THE ROTOR.

Quote

But it seems the spring will put mild pressure on the caliper to further drag the brake pad not on the piston side.
Putting a optional spring in the mix seems to put one pad further from rotor, which has to put the other pad closer to the rotor?

THERE IS A PISTON RETURN SPRING ALREADY ON THE INBOARD (PISTON) SIDE OF THE CALIPER.

Re: Helper springs on Meritor disc brakes

Reply #24 – December 11, 2012, 11:18:40 am

Thanks Brett,

I now see that both photos have the spring in the correct location.

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