Front Drum to Disc Brakes

[LargeCar]

2009 Carribean on a Freightliner XC chassis.

Has anybody done a drum to disc brake conversion?

Wondering if I can just change from the spindles out or if an entire axle change would be required. What about a proportioning valve, is it required?

Just tired of trying to get those danged squeaking brakes fixed. Maybe a full on complete brake job is in order. New drums and shoes. But then what do I do when they go to squeaking again?

To many questions.

Thanks

 

[Chuck v]

Changing any vehicle braking setup from all drums to a hybrid of disc and drum requires careful engineering. This is particularly true for larger vehicles and/or those with anti-lock systems. I suggest you try to evaluate the use habits of your coach first.



My 2007 XC chassis did not have issues with performance, and any 'squeaking' experienced seemed to be from too light a usage pattern.


Have you tried periodically blowing the dust out of the drums when you begin to have the squeaking present??? Do you seldom use the coach at road speeds and are you in the habit of using the exhaust breaking to do much of the slowing? If so, try using our service brakes a bit harder to break the glaze on the drum and pads.


Here is a typical post from other owners of this chassis...
https://community.fmca.com/topic/3754-noisy-service-brakes/


Chuck

 

[LargeCar]

I have had the drums off and used a commercial brake cleaner on the drums and shoes. That did not work. I took the drums off and sanded the shoes to remove any glazing and the drum the same. That did not work. I then took the drums off did a much more aggressive sanding (grinding) of the shoe and drums. That did not work. I swapped drums side to side and that also did not work.

I cannot use my exhaust (turbo) brake because it throws the ECU into limp mode and I have to cycle the key to clear it.

I have several million miles under the belt in big rigs (see forum handle) so I don't think it is an application issue.

Maybe the answer is rather than going to disc brakes go with two new drums and softer blocks on the shoes.

Thanks for the reply. Maybe you helped me by making me think it thru a bit more. Any suggestions on the exhaust brake issue?

LC

 

[LargeCar]

Explanation of forum handle.

Grandkids say a big truck goes as fast as it can, a Largecar goes as fast as it wants.


LC

 

[Chuck v]

You do need to fix the exhaust brake, but I don't have any specific suggestions.

My Mercedes turbo diesel engine did not have any compatibility issues with the exhaust brake, but maybe you have a different engine...

Hope you find a solution to your issues. Are you aware of any aftermarket disc conversions that are made specifically to fit the XC chassis, and do they have all the needed ABS interactions/connections/balancing?? I have attached the XC flyer that shows the drum system all around has ABS...just in case you don't have it.


I have seen this about converting/updating other Freightliner trucks but cannot verify the prices or accuracy...

If you have Eaton axles no disc conversion available. If you have Meritor axles you will need backing plates, calipers, discs, hubs, air lines, bearings and possibly axles depending on length required. Just about everything that mounts to the wheel end and out. Also if you have ABS you need to make sure the tone wheel is the same. As for the steer axle you will have to replace the front axle to get the right one for the spindles then backing plates, calipers, discs, air lines, hubs with bearing seals etc. Bad thing about the disc breaks is if you don't know how to adjust them OE have someone that doesn't you will go thru a bunch of shear pins until you learn. Best thing about them is you can change pads in about 2 minutes with the wheels off. Cost for conversion with new parts is ballpark around $8400. Labor is on top. The rear backing plates may require modification where they mount to axle. Depends on what axle you have. Labor is how fast you can spin your wrench or about 17-20 hours at a dealership. You will also need alignment since the front axle is replaced. You can bet 10 grand or so might get you close but no promises.
​

Chuck

 

[hossross]

2009 Carribean on a Freightliner XC chassis.

Has anybody done a drum to disc brake conversion?

Wondering if I can just change from the spindles out or if an entire axle change would be required. What about a proportioning valve, is it required?

Just tired of trying to get those danged squeaking brakes fixed. Maybe a full on complete brake job is in order. New drums and shoes. But then what do I do when they go to squeaking again?

To many questions.

Thanks

Drum brakes are better than disc for not dragging and simpler parking brake. Performance is similar, disc can disappate
heat faster. But that under extreme braking, otherwise no advantage to user. I agree with Chuck, mfg do testing and design iterations after market typically doesn't, so I talk to one who has lived with a conversion before spending 10k.
Technically the noise comes from a vibration, probably excited from shoes doing instantaneous stick/slip. The noise comes from something that resonates/ vibrates as a result to excitation force. There are apps that measure the noise frequency. See if same noise in all stopping conditions. Usually each noise comes from a different place with brakes. As an engineer, I'd say something is out of specs. And in your case a manufactured, not from wear. If warranty is not a choice, then I'd change shoes to softness material available. Long life shoes typically will cause noise more often Are your shoes bonded well to shoe metals? If the S cam is often a problem get highest temp brake lube and use on it. Both on pivot and contact surfaces. For sure Id replace some brake hardware & shoes before thinking of disc. Good luck