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By Titchbitch
#1860615
Hi guys,
I have recently bought a Taylor Titch that hasn’t flown in 4 years and the toe brakes are both on full deflection (as in full brake position) and won’t move. I can’t see both master cylinders are seized surely? They are Matco MC-4A’s if that helps. Could it be a hydraulic lock or something similar? Is it worth completely draining the system to see if that’s causing it?
Any help is much appreciated!
By A4 Pacific
#1860656
I guess you’ve already tried unscrewing the bleed nipple at the caliper draining and then flushing the brake system from there back up to the cylinders?

The pedal brakes are often kept in the ‘off’ position by springs. Are they compressed?
Last edited by A4 Pacific on Fri Jul 23, 2021 9:51 am, edited 2 times in total.
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By Rob P
#1860657
You don't make clear if the brakes are locked on or not.

Rob P
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By A4 Pacific
#1860660
TBH, brakes aren’t something to be messed around with. Perhaps particularly so on a light taildragger. If there’s any doubt whatsoever about their serviceability, remove the entire system, understand and then rebuild them as required. Or accept the risk of finding yourself upside down with your head on the tarmac/grass, unable to vacate the a/c.
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By Titchbitch
#1860731
They are disk brakes. The brakes at the calipers at least are off, but both master cylinders are compressed. Having perfect brakes on a light, short coupled tail dragger are rather important! We haven’t yet flushed the system which we are planning to do this weekend.
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By Sooty25
#1860751
I agree with @johnm . Matco's are simple to overhaul, just remove and strip.

But if it hasn't flown for 4 years, I guess you are going through the entire aeroplane anyway.
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By MikeW
FLYER Club Member  FLYER Club Member
#1860822
Also agree with johnm. The callipers are probably seized from corrosion outside the piston seal.
There is abundant information on the Matco website about servicing and parts. The calliper seals are ordinary O rings and you can get the size from the Matco drawings. They (usually) match BS sizes and designations and cost pennies from e,g simply bearings or bearingboys. I think mine were BS222 37.69mm ID x 3.5 mm dia section (1.5" x 9/64"), that's for Matco's smallest calliper. Normal nitrile material (also known as Buna N) if you're using red mineral fluid (DTD585) but not car brake fluid, EPDM for that (unless silicone DOT5, vile stuff).
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By cockney steve
FLYER Club Member  FLYER Club Member
#1860833
As pads (or shoes wear, the reservoir tops-up the master-cylinder. When you brake, you close that "valve and the pressure diverts the druk/disc (caliper or wheel-cylinder. the fact the prake-pedals are"on the floor" would indicate that your problem lats in BOTH master-cylinders. (yes, they probably have the same problem as they had the same prolonged inaction. further guess- seized pistons ir push-rods.. :?:

edited for fat fingers -again.! :oops:
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By Titchbitch
#1860904
Thanks all for the input, turns out we are being a little thick! The master solo sets were not seized at all! On full deflection the toe brakes raise a bit so you have full manipulation at the full extent (we didn’t notice!). Fluid completely drained and replaced with fresh oil and bled the system and everything works beautifully!
Thank Christ for that!
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By Titchbitch
#1860963
All good, there was no leak in the system, it just hasn’t been used in years. Also I used the correct 5606 (aeroshell 41) that is required for the matco master cylinders and the Cleveland calipers. The reservoir was full before we even touched the system. We flushed the system of the old oil & replaced with the new fluid.
By johnm
FLYER Club Member  FLYER Club Member
#1860965
Titchbitch wrote:All good, there was no leak in the system, it just hasn’t been used in years. Also I used the correct 5606 (aeroshell 41) that is required for the matco master cylinders and the Cleveland calipers. The reservoir was full before we even touched the system. We flushed the system of the old oil & replaced with the new fluid.


That's all quite encouraging, but I'd still strip and renew seals in one that hasn't been used for that long.....
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