Unofficial Royal Enfield Community Forum

Royal Enfield Motorcycles => Bullet with the UCE engine => Topic started by: REdmonton on March 29, 2016, 06:34:59 am

Title: Brake Master Cylinder Screw Stripping
Post by: REdmonton on March 29, 2016, 06:34:59 am
I had to do some work on the front brake of my Desert Storm. When I tried to open up the Master Cylinder Top Cover screws/bolts the head on one of the screws started to strip out. Any suggestions on fixes? Anybody know the size of the bolt?
Title: Re: Brake Master Cylinder Screw Stripping
Post by: krusty on March 29, 2016, 12:07:22 pm
This is a problem I have encountered on some of my previous bikes, mostly Suzukis, I now use an impact screwdriver.  Tread lightly though, just a few gentle taps with a 8 ouncer should do it. Use a really nice fitting bit.
If the screw is screwed, try knocking it round with a small pointed punch. They usually come out without too much of a fight.
Title: Re: Brake Master Cylinder Screw Stripping
Post by: Sectorsteve on March 29, 2016, 01:24:22 pm
My screw heads on the master cylinder just sheared off the screw leaving  the screw to be removed from the master cylinder. Trying to rack my brains , what I did! Think I either used a really small drill bit....no that's right, there was a bit sticking up I could get pliers onto. Get the screw out and take it to yr local nuts n bolts store to get the size!


I had to do some work on the front brake of my Desert Storm. When I tried to open up the Master Cylinder Top Cover screws/bolts the head on one of the screws started to strip out. Any suggestions on fixes? Anybody know the size of the bolt?
Title: Re: Brake Master Cylinder Screw Stripping
Post by: sparklow on March 29, 2016, 03:00:11 pm
When you do get those screws out, use some anti-seize on the new ones!
Title: Re: Brake Master Cylinder Screw Stripping
Post by: johno on March 29, 2016, 06:07:38 pm
This problem has happened to nearly every bike I have owned, due to living on the coast in a salt air environment.
The best thing to do is carefully drill off the heads, no further than is needed to collapse the head.
lever off the brake master lid, then use mole grips (self locking pliers) to unscrew the remains of the screws.
Replace these with stainless hex socket (allan screws) machine screws, but make sure the threads have a coating of copper grease to prevent further corrosion.
Title: Re: Brake Master Cylinder Screw Stripping
Post by: suitcasejefferson on March 29, 2016, 11:11:04 pm
I've had this problem on nearly every Japanese bike I've ever owned. I see 3 reasons. One, the screws were overtightened on assembly. Two, they are made of VERY soft metal. Three, while they may look like Phillips screws, they are actually JIS, or Japanese Industrial Standard screws. There is a difference. I now have a set of JIS screwdrivers, but found that a fluted #2 drywall bit works well. It should work on the RE too. Put the bit in the screw and tap on it with a hammer for about 2 minutes before trying to turn it. You have to be very careful with these things. I destroyed a $150 master cylinder once, because I broke off one of the screws even with the reservoir, then cracked the reservoir trying to get it out.

Also, a bit unrelated, but if your bike spends a lot of time in the sun, I would put a piece of aluminum foil tape over the sight glass. It's not real glass but some kind of plastic, and the sun will deteriorate it fairly quickly. I've repaired several master cylinders by filling the hole where the plastic sight glass deteriorated and fell out with JB Weld, and grinding it flat.
Title: Re: Brake Master Cylinder Screw Stripping
Post by: The Old Coot on March 30, 2016, 07:33:14 pm
I make it a habit to replace those screws with Stainless Steel Hex Head screws. The after they are in tight I drip a little bit of hot candle wax in the hex hole and let it cool. I have to replace the wax on a timely basis but it keep water from sitting in the hole and causing problem later.
Title: Re: Brake Master Cylinder Screw Stripping
Post by: Ducati Scotty on March 31, 2016, 04:01:46 am
Too late now, but I make a habit of putting the screwdriver in and giving a few nice taps with a hammer before trying to undo them on any bike.  The master cylinder screws seem to always be tight as a lug nut while also being made of very soft French cheese.  A few taps usually breaks the grip and let's me get them out without stripping. And if you have a JIS screwdriver, so much the better.  JIS screws have a dot on the head next to the cross of the slot. 
Title: Re: Brake Master Cylinder Screw Stripping
Post by: heloego on April 01, 2016, 10:14:21 pm
JIS bits or a #2 drywall bit with a few taps work great. I hedge my bet by dipping the bit in valve lapping compound.
Title: Re: Brake Master Cylinder Screw Stripping
Post by: REdmonton on April 02, 2016, 12:29:48 am
I picked up an impact screwdriver. A couple of taps and it loosened right up.   :) Downside is that I couldn't free the brakes up. I had the the same problem at Singh5 did with his caliper getting stuck but I couldn't get it freed up.  :( After a trying for days I gave up and brought it into the shop.
Title: Re: Brake Master Cylinder Screw Stripping
Post by: Barnone on March 11, 2019, 12:27:26 am
This problem has happened to nearly every bike I have owned, due to living on the coast in a salt air environment.
The best thing to do is carefully drill off the heads, no further than is needed to collapse the head.
lever off the brake master lid, then use mole grips (self locking pliers) to unscrew the remains of the screws.
Replace these with stainless hex socket (allan screws) machine screws, but make sure the threads have a coating of copper grease to prevent further corrosion.
Somebody ( previous owner?) buggered up the screw head on one of the screws that hold the cap on. I tried an impact driver to no avail. Next I night try your method of drill off the head.
I am new to RE, where is a good parts source in case I have to replace the master cylinder?
Title: Re: Brake Master Cylinder Screw Stripping
Post by: Dalmatian man on March 11, 2019, 09:38:13 am
Screw size  4mm  0.7mm pitch
Title: Re: Brake Master Cylinder Screw Stripping
Post by: Barnone on March 11, 2019, 04:03:03 pm
Screw size  4mm  0.7mm pitch
Got some stainless steel screws at the hardware store.
The drill off the head of the buggered one and remove with vice grips worked.
Also replaced the screws on my TU259X.
Used a little anti siege.
Thanks
Title: Re: Brake Master Cylinder Screw Stripping
Post by: johno on March 31, 2019, 10:11:34 pm
Got some stainless steel screws at the hardware store.
The drill off the head of the buggered one and remove with vice grips worked.
Also replaced the screws on my TU259X.
Used a little anti siege.
Thanks

It's a pleasure  :)