MC1 Brakes.

[johns4104s]

Does the MCI 9 (1981) come with spring brakes or DD3 Brakes on the drive axle?

Thanks

John

[Sojourner]

DD-3

Sojourn for Christ, Gerald

[johns4104s]

Gerald,

I here that there are all sorts of problems with DD3,s/including cost. Do you know if it is easy/possible to change over to spring brakes?

Thanks

John

[gumpy]

Gerald,

I here that there are all sorts of problems with DD3,s/including cost. Do you know if it is easy/possible to change over to spring brakes?

Thanks

John

Don't believe everything you hear.

[johns4104s]

Grumpy,

If you know anything about these brakes or have any experience running with them how about sharing it?
I added spring brakes to my 04, 20 years ago and never had a brake binding problem like I experienced last week???

John

[Lin]

There have been threads in the past comparing the two systems.  Each has its pros and cons.  I am sure that DD3's are very common with the people on this board.  My last bus had spring brakes, and this one has DD3's.  The chambers for DD3's are over 10 times the cost of 30/30 pots.  However, aside from that, there does not seem to be any serious disadvantage to them and they are equally dependable.  It is possible to change them over to spring brakes if you have room to do so.  That however, is not without its own costs.  If you have to buy new chambers, you could look at the two options and decide.  If the issue is your concern about a past experience with them, it does not seem to be worth the effort; just keep them well maintained.

Incidentally, I once watched a trucker with frozen spring brakes trying to move them with a pry bar.  Things happen.

[johns4104s]

Lin,

Thank you for the info,

On my 04 I changed them out myself at $65 per side ( this included like you said the e double chambers, one for the brake and the second for the spring chamber) I also changed out the rubber hoses $9.00 each. So I was interested in seeing the possibility of doing the same, as I did not like seeing a passer by honking.waving and pointing to the rear driver side drive Axel with smoke pouring out. I had road service come out and pull the tires. I checked the slack adjuster and backed it off some. Made sure the brake was not binding. No problem for the past 400 miles.
But like you said will they FIT? It looked tight to me, the slack adjuster and brake can. Does anyone Know? Has anyone changed them over?

Thanks

John

PS I have a friend with a MCI 5 who changed his system to the spring brake. I realise that this is not the same bus but he changed because he had a brake problem and the new cans where going to cost him $600 each??

[Tom Y]

John, Can you put me in touch with the 5 owner who changed over to springs? I looked at mine and could not make them work without a torch and welder.  Thanks Tom Y

[Don4107]

There is more to changing from DD3s to spring brakes than just swapping the brake pots.  There are other changes to the parking system required.  Not a huge problem, but it needs to be properly set up

Good luck
Don 4107

[ol713]

Hi All;
      I would vote to keep it simple.
      Just rebuild the DD3's and drive
      on for another 10yrs or so.
                  Good luck,   Merle.

[gumpy]

There's absolutely nothing wrong with DD3 brakes if they are properly maintained. However, just like everything else on your bus, they will wear over time, and will eventually need to be replaced. The more you neglect them, the faster they will wear out.

Rebuilt DD3s are available for around $500. I think there's also a kit you can get to rebuild them yourself, but not completely sure about that.

It's very unusual for a DD3 to stick like you said happened to you. It's usually a result of neglect and improper maintenance (maybe not by you, but by somebody). That being said, it's also possible for spring brakes to fail due to neglect. Replacing DD3s with spring brakes is not a bolt on change. Modifications to the mounting structure need to be made, and clearance is an issue. There are also changes in the air valves that need to be made.

My suggestion would be to fix the brakes you have, and learn to maintain them properly. They'll outlast you, and won't give you any problems.

craig

[johns4104s]

A retired Greyhound mechanic shared that he never understood why coach builders used DD3 when spring brakes were cheeper and just as good. Maintainence of any system is a must. He also said there should be plenty of room on the MCI 9 to fit them.

John

[RJ]

A retired Greyhound mechanic shared that he never understood why coach builders used DD3 when spring brakes were cheeper and just as good. Maintainence of any system is a must. He also said there should be plenty of room on the MCI 9 to fit them.

John -

One of the reasons DD3s were used was a safety factor.

With normal spring brakes, when you push the button, the coach will roll.

With DD3s, generally you have to make a full service brake application after pushing the button in order to get the brakes to release.

Because of that, it reduces the risk of some passenger playing games with the parking brake button while the driver is not behind the wheel (loading/unloading luggage, taking tickets, etc.).

Believe me, it DOES happen - especially with 8 year old boys!  Don't ask me how I know. . .


I would tend to agree with Craig about the problem you had - poor prior maintenance.

Changing over to spring brakes will be a project.  Naturally, besides the new cans, you'll have to replumb the air system accordingly.  Careful scrutiny of the coach's air system schematics will be required.  Not insurmountable, but a bit different than your previous project of adding springs to the old 4104.

Perhaps proper maintenance of the DD3s would allow more time and $$ for other bus projects??

FWIW & HTH. . .

[johns4104s]

RJ,

Your input as always digs right to the core of the problem. You hit the nail on the head, yes unlike the trucks, Greyhound and tour passengers have to be considered.
My MCI 9 has very little miles since it was converted, which included rebuilt 8V92 and new HT750.maybe 5,000 miles in 6years, so it just stood., I purchased it some months ago. I am very familiar with the 04 but not the MCI 9. I will be pulling lot of maintenance on this coach. I don't use the coach every weekend either so I could be continuing with this problem. As I have had spring brakes on the 04  for the past 20 years, with no problem. Also with the spring break cost being 10% of the DD3 system if possible and they will fit I will be changing over.

John

[Sojourner]

John4104s...I am planning on installing spring cans when I am ready to do it. It going to be remount with new can's mount bracket. Either one is already made for truck or make one "non-weld" like OEM design but longer & relocated mounting holes to axle housing.
Craig's site has a great photo of a MCI-9's driver side view of DD-3 position: (http://www.gumpydog.com/bus/MC9_WIP/Mechanical/Drive_Axle/031019.11.new_drive_axle_air_bags_installed.JPG

My MCI-8 is the same as 9's.

It can be done but it will be on your own decision to build, installed and be responsible if anything failed or injuries.

Spring can assembly need to be raise & rotate some to be in area of 5-10° from its OEM position of about 40° so the spring end of can to cleared air spring (bag).

Whatever you do, if any mounting part are fabricate welded, always anneal the part to stress relieved before install.

BTW...DD-3 is disassembling & reassembles fairly easily if you are an overhauling mechanic. However, "spring can" assembly, you cannot open spring can's end because it sealed to avoid injuries but the rest is repairable. Back in early 60's, they were unsealed and yes I did repair them with caution and care.

FWIW

Sojourn for Christ, Gerald