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Matco Master cylinders

M

martinair

Member
Hi guys,

looks like one of my master cylinders failed and I want to overhaul them or maybe even replace both.

The problem is it doesn't show which type it is, I believe Matco MC-4, but I don't know which variant. My RV4 is from 1998, and I didn't find anything in the paperwork.

Can somebody please tell me which exact master cylinder it is, there are so many different on Matco's website?

Thank you and kind regards from Germany, Martin

Matco.jpg
 
martinair said:
Hi guys,

looks like one of my master cylinders failed and I want to overhaul them or maybe even replace both.

The problem is it doesn't show which type it is, I believe Matco MC-4, but I don't know which variant. My RV4 is from 1998, and I didn't find anything in the paperwork.

Can somebody please tell me which exact master cylinder it is, there are so many different on Matco's website?

Thank you and kind regards from Germany, Martin

View attachment 57881
Click to expand...
I suggest, buy new, those don’t rebuild very good. Maybe consider an upgrade to Grove Master cylinders. they are expensive but well worth the investment.
 
Here is a repair kit from Van's, for $24. As far as I know the same model Matco master cylinder has been supplied. Earlier master cylinders were by Cleveland and are clearly different.

store.vansaircraft.com

BRAKE M/C RBD4 REPAIR

Master Cylinder Rebuild Kit
store.vansaircraft.com store.vansaircraft.com
 
martinair said:
unfortunatly that's not the one I have. It's different.
Click to expand...
Martin,

The master cylinder is an MCMC-4F(S). It can most certainly be rebuilt with the kit mentioned above. Just make sure the bore isn’t damaged. If so, then you’ll need a new master cylinder. Inspect the shaft very carefully. It should be perfectly smooth. If it’s not, that can be replaced very inexpensively too.

matcoals.com

MASTER CYLINDER, Center Slotted .62 - Matco Aircraft Landing Systems

Center Slotted Master Cylinder, .62
matcoals.com matcoals.com

Check out the drawings at the bottom of the page. I just ordered the shaft for mine. I was hoping to just rebuild it, but the shaft was marred. The geometry of the RV master cylinder attachment has a lot to do with why it got marred. But then again I got 17 years and almost 2000 hours out of it. PM me your email address and I’ll send you some info I just got from Matco tech support.

Also, you can get the rebuild kit for less money from Aircraft Spruce or Matco.

Jerry
 
Go to matcoals.com to the master cylinders page and they list the various versions and also have the repair kits.
 
RV8Squaz said:
Martin,

The master cylinder is an MCMC-4F(S). It can most certainly be rebuilt with the kit mentioned above. Just make sure the bore isn’t damaged. If so, then you’ll need a new master cylinder. Inspect the shaft very carefully. It should be perfectly smooth. If it’s not, that can be replaced very inexpensively too.

matcoals.com

MASTER CYLINDER, Center Slotted .62 - Matco Aircraft Landing Systems

Center Slotted Master Cylinder, .62
matcoals.com matcoals.com

Check out the drawings at the bottom of the page. I just ordered the shaft for mine. I was hoping to just rebuild it, but the shaft was marred. The geometry of the RV master cylinder attachment has a lot to do with why it got marred. But then again I got 17 years and almost 2000 hours out of it. PM me your email address and I’ll send you some info I just got from Matco tech support.

Also, you can get the rebuild kit for less money from Aircraft Spruce or Matco.

Jerry
Click to expand...

Actually disregard the model number. Yours looks different than mine. However, you should find what you need on the Matco website. If no, email them. They were very responsive via email.
 
RV8Squaz said:
Actually disregard the model number. Yours looks different than mine. However, you should find what you need on the Matco website. If no, email them. They were very responsive via email.
Click to expand...
Hi Jerry,

I emailed them parallel to my enquiry here and I got a very quick answer: I seem to have MCMC-4F(R) and MCMC-4F(L). Since mine are now over 25 years old I will just replace them. I already tried to overhaul them, that repair with new seals failed on both. I don't want to remove them from the aircraft for a 3rd time.

thanks again for the replies.
 
martinair said:
Hi Jerry,

I emailed them parallel to my enquiry here and I got a very quick answer: I seem to have MCMC-4F(R) and MCMC-4F(L). Since mine are now over 25 years old I will just replace them. I already tried to overhaul them, that repair with new seals failed on both. I don't want to remove them from the aircraft for a 3rd time.

thanks again for the replies.
Click to expand...
Smart man that Martinair. If it old just get new. Deal done. Problem solved
I just rebuilt my Matco's last week.
My luck varies FIXIT
 
RV8Squaz said:
... I was hoping to just rebuild it, but the shaft was marred. The geometry of the RV master cylinder attachment has a lot to do with why it got marred.


Jerry
Click to expand...
Jerry, what is it about the mounting that promotes the shaft damage? On my -8 I put the right number of spacer washers under the pushrod attachment at the pedal so it would line up straight. Is that the issue you found? That there was a side load on the shaft because the pedal attach point was not straight above the base attachment?

I'm asking now because I am adapting two sets of ground-adjustable RV-8 rudder pedals to fit in my Hatz. I will once again tune the attachment so that everything lines up straight.
 
scsmith said:
Jerry, what is it about the mounting that promotes the shaft damage? On my -8 I put the right number of spacer washers under the pushrod attachment at the pedal so it would line up straight. Is that the issue you found? That there was a side load on the shaft because the pedal attach point was not straight above the base attachment?

I'm asking now because I am adapting two sets of ground-adjustable RV-8 rudder pedals to fit in my Hatz. I will once again tune the attachment so that everything lines up straight.
Click to expand...

Hello Steve,

This is straight from tech support at Matco. In the attached picture of my installation, you’ll see how my bolt is a little cocked and that’s with no load. I may fix it the way he suggests but then again, I did get 17 years and almost 2000 hours out of mine. The attachment he refers to are those that are found on their website.

“The master cylinder needs the load down the centerline of the cylinder. When done so, there is no bending loads in the shaft that can cause the piston shaft to rub against the end gland. The VANS installation does not put the load down the center of the cylinder as desired. The connection at the shaft end uses a bolt that imposes an offset load. The offset load results in a moment that has to be reacted by the shaft. This typically results in the piston in the bore and the shaft at the end gland reacting the moment. This will cause wear on the shaft at the cylinder. The shafts must be able to fully extend when at rest for the hydraulic system to work properly and self-adjust as explained in the attached document.
There is an AN bolt on the toe brake that is loosely attached to a lug. Then a series of washers are installed to space the shaft in position. Since the bolt is not able to carry any moment, the shaft must carry it. It results in the shaft rubbing on the end gland which leads to scratches on the shaft which eventually damage the seal in the ID of the end gland. Some of the VANS pedals have a flange on both sides of the pedal that allow a long bolt to pass through both flanges and then attach to the shaft. I believe the RV-8 is one of them. This type mounting will allow the bolt to carry the moment and will eliminate the problem. It looks like yours is of this type. Others have stiffened the lug and used an all-thread bolt so that the bolt can be tightened against the lug with a nut. The now cantilevered bolt will carry some of the bending moment and relieve the shaft. Some simply use the all-thread bolt and nut which helps but the stiffness is likely not enough to eliminate the problem completely although it is helpful.“IMG_1432.jpeg
 
Thanks Jerry. Yes, I see that because the bolt is left loose so the shaft can rotate as the pedal rotates, it doesn't matter that the correct number of washers are there to make it all line up straight. The bolt still can change angle a little, putting a moment into the shaft. The best thing for this application would be a shoulder bolt that would pull up tight against the pedal and act as a cantilevered post. But it is only a 3/16" hole, so not enough diameter for a decent strength shoulder bolt. Next best thing would be to substitute a jam nut in place of the stack of washers, and tighten the jam nut and the end nut both against the pedal, again making the bolt a cantilever post for the shaft to turn on.

Thanks for sharing this. I'll try the jam nut solution on the Hatz pedals and then retrofit my RV-8 pedals during next condition inspection.
 
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