MC1 Brakes.

[buswarrior]

The Greyhound mechanic didn't know what he was talking about...it is a big job to retrofit spring brakes into an MC9.

You will have to fabricate new mounts, cutting and welding to proper strengths, as the spring chambers won't fit in the space of the DD3, note the proximity of the air bellow to the back of your DD3, and the limited choices as to where to stuff that spring chamber in anywhere that would be a neat install.

You will have to do some re-plumbing, your DD3 parks with air, your new springs will release with air...

Yes, DD3 chambers are expensive, captured market, charge what the market will bear.... trade in your cores, or re-build them yourself. Local charter company that is selling it's last DD3 buses will be dumping the inventory...some savings there for the astute busnut....

But, once you put in fresh chambers and a fresh Inversion valve, you'll be done, with perhaps a simple diaphragm change needed sometime over a decade or more from now.

I'm just maintaining the DD3 that are there and finding other things to re-engineer that aren't as critical.

happy coaching!
buswarrior

[Ncbob]

Tom Y,

I can tell you from experience that your rear DD3 actuators and Left and Right. Having gone through mine I can advise you that it would cost you more to change to spring brakes than you bus is worth.
I love my '5' but...it ain't practical. There just isn't enough room. You get in there and mess around with them like I did and you'll wish you hadn't.

The DD3 system on these old buses is a fine system. It's antiquated, like our buses, and if respected, will work fine. You CAN change the diaphragm's yourself, according to Cliff, and be fine. Keep the brakes adjusted properly and drive safely.

NCbob

[Tom Y]

NCBob, Yes I agree. I looked at mine before rebuilding the DD3s. I wanted to talk to someone who changed to see what they did.  Thanks Tom Y

[Lin]

I think that BW has it right.  There are lots of things on an old bus that could be more modern but really make no difference at all.  DD3 brakes are one of them.  The idea of going through the effort to convert to spring brakes to make it cheaper to replace the pots 10 years from now would be very low on my list of priorities-- somewhere above making the bus seaworthy.   Truthfully, if I am still using this bus at that time, I would consider it a blessing to buy new chambers for it.  It's sort of like having to pay a million in income tax; I really wouldn't mind having that income.