Collective Wisdom & Tips on Replacing SMC Needed

I'm about to replace my SMC with a new one and would like your collective wisdom & tips.

Can I remove the SMC from the caliper without opening the caliper banjo bolts or do I have to remove both SMC & caliper from the bike?
I'm hoping I only have to remove the 2 SMC banjo bolts.

Do I have to re-flush the whole brake system to replace only the SMC or do I only need to re-flush 1 or 2 of the brake flush sequences?

Thanking you for your input in advance,

Andy

Yes you will have to remove the banjo bolts and yes you will need to do a complete and proper bleed on the fluid.

Here is a good article on this https://www.st-owners.com/forums/showthread.php?133460-ST1300-Secondary-Master-Cylinder-Rebuild-SMC&highlight=

Purm1300 said:

do I have to remove both SMC & caliper from the bike?

Click to expand...

Assuming you are replacing the SMC, there is no need to remove the caliper from the bike.

Do I have to re-flush the whole brake system to replace only the SMC or do I only need to re-flush 1 or 2 of the brake flush sequences?

Click to expand...

Though there may not be a "need" to bleed the lever circuit, that is the easy one to do and you might as well do the whole system while you are at it. Be sure and bleed everything in sequence according to the manual.

At the bottom of this page, I've listed a bunch of SMC threads that I had archived from when I did the job. Read them all to get a feel for the job before you dive in for the first time. Pay particular attention to anything IGOFAR has to say about the matter. He is our resident expert for all things brakes.


Some tips for the first time you do this job:

1. If you don't have a service manual, get one.

2. I completely removed the front wheel & fender to make things easier to see and remove.

3. Before disconnecting anything on the SMC, take plenty of pictures showing where everything attaches, how it's routed, and how each connection is positioned. The pics may or may not be needed but it helps keep potential fubars at bay and removes uncertainty when putting everything back together.

Here is a word document that contains the pictures I took prior to disconnecting my SMC. Feel free to downloaded it:

http://users.hal-pc.org/~mmcham/SMC_Pics.doc


4. Prior to removing anything, have enough new, banjo washers on hand to hook everything back up when finished.

5. There is no need to drain the hydraulic system prior to doing this job as the service manual mentions. You'll find that there is very little leakage of fluid once the hoses are disconnected. The air that is introduced will be taken care of when everything is buttoned back up and you bleed the system.

6. Use a torque wrench.


My archived SMC threads on the subject. Somewhere in these threads is a list of steps by IGOFAR:
*****************************************************************
https://www.st-owners.com/forums/showthread.php?120746-Replacing-the-SMC

https://www.st-owners.com/forums/showthread.php?120665-Brake-bleed-experience&p=1519414&viewfull=1

https://www.st-owners.com/forums/showthread.php?68913-ST1300-Brake-Fluid-Replacement

https://www.st-owners.com/forums/showthread.php?53678-ST1300-Brake-Bleeding-Sequence-Cheat-Sheet

https://www.st-owners.com/forums/showthread.php?68913-ST1300-Brake-Fluid-Replacement

https://www.st-owners.com/forums/showthread.php?106729-Secondary-Master-Cylinder-FAILURE!

https://www.st-owners.com/forums/forumdisplay.php?456-ST1300-Brakes/page6

https://www.st-owners.com/forums/showthread.php?86791-SMC-Rebuild-Kit

Make sure that you have a decent set of snap-ring pliers with straight tips. The snap ring that holds the plunger in sets in a recessed groove and is very difficult to remove without them.

mlheck said:

Make sure that you have a decent set of snap-ring pliers with straight tips. The snap ring that holds the plunger in sets in a recessed groove and is very difficult to remove without them.

Click to expand...

He shouldn't need these since he is replacing the whole SMC.

Thanks so much Mick. I already have all of the components you mention ready to go.

I was just looking to have to open the least number of banjo bolts and avoid a full flush (I just flushed the entire system last fall when I put my bike in storage) if possible.

I am installing a new SMC.

Thank you.

Andy