Removing brake master cylinder screws :mad:

[nigelp]

Hi all

I have noticed that my brake lever is are getting a bit hard to pull lately so I thought I would check the level of fluid in the reservoir on my bars. I went to undo the two screws and they wont come loose! They are as tight as a nun on Sunday! Any ideas on how to loosen them up so I can have a peek inside?

TIA
Nige

[imdying]

Impact driver usually works on those. Otherwise you'll have to get a stout flat head and bash them round.

[dhunt]

Get a philips screwdriver (This assumes they are philips heads) and tap it with a hammer as you turn it. Seems to work a treat for me.

You master cylinder does have a clear panel on the side that you can see the level of fluid.

You problem doesn't seem to correspond to your solution. Are you positive the lever is harder to pull in. Softer I could understand but not harder. Apart from this can you still stop as quickly?

[vifferman]

Get a philips screwdriver (This assumes they are philips heads) and tap it with a hammer as you turn it. Seems to work a treat for me.

Yeah, what he said (don't use an impact driver - the reservoir's not up to it).
When you get it out, put a small smear of grease on the threads. It's common to get brake fluid down the holes of the reservoir, and it phUxx0rs the screws.

[nigelp]

Get a philips screwdriver (This assumes they are philips heads) and tap it with a hammer as you turn it. Seems to work a treat for me.

You master cylinder does have a clear panel on the side that you can see the level of fluid.

You problem doesn't seem to correspond to your solution. Are you positive the lever is harder to pull in. Softer I could understand but not harder. Apart from this can you still stop as quickly?

Awesome, thats for the information, will try tonight with the flat head screwdriver.

My brake lever is definately "hard" to pull and it appears that my pads are fine. Any other ideas why it could be hard to pull? There is also a slight shudder if I brake hard, maybe the rotor is bent from my off road trips....

[F5 Dave]

Hard to pull - or you have to pull it hard to stop?

Fluid level will have nothing to do with it, Fluid condition will make it less spongy & should be changed periodically (yearly would be nice).

The pistons in the calliper are likely partially seized. Taking it off, pumping them out a bit, clean up & Carefully push back in (pads removed, I use tiny sash clamp to push back in ~$4 Supercheap or Wh) may be all it needs.

Check pads aren’t glazed. Rough up on v.smooth concrete or sand paper can help. The shudder can be pad glazing or compound, but not often, If you feel anything at the lever pulsing then it is disc warp. Above seized pistons would overheat disc.

All that said have a look at the lever assembly if still hard. Not Japanese quality so something could be dicky. Check lever bolt lubed, not binding.

With the cylinder screws I have in the past had to grind a flat into the heads of the bolts that have been stripped with a dremel cutter (careful of lid). But sometimes it is a small wood chisel to make an angle cut into the bolt head then a sacrificial flatblade screwdriver (every one should have a cheapo screwdriver for doing what you shouldn’t with your good ones ) to angle tap it anti clockwise.

[nigelp]

Hard to pull - or you have to pull it hard to stop?

Fluid level will have nothing to do with it, Fluid condition will make it less spongy & should be changed periodically (yearly would be nice).

The pistons in the calliper are likely partially seized. Taking it off, pumping them out a bit, clean up & Carefully push back in (pads removed, I use tiny sash clamp to push back in ~$4 Supercheap or Wh) may be all it needs.

Check pads aren’t glazed. Rough up on v.smooth concrete or sand paper can help. The shudder can be pad glazing or compound, but not often, If you feel anything at the lever pulsing then it is disc warp. Above seized pistons would overheat disc.

All that said have a look at the lever assembly if still hard. Not Japanese quality so something could be dicky. Check lever bolt lubed, not binding.

With the cylinder screws I have in the past had to grind a flat into the heads of the bolts that have been stripped with a dremel cutter (careful of lid). But sometimes it is a small wood chisel to make an angle cut into the bolt head then a sacrificial flatblade screwdriver (every one should have a cheapo screwdriver for doing what you shouldn’t with your good ones ) to angle tap it anti clockwise.

I would imagine that the fluid has never been changed, and the bike is a couple of years old now so will try that. I will also take the pads off and have a look at the pistons.

Will also have a look at the other things you mention.
Thanks

[quickbuck]

There is a product we use at work called screw-grab.
This is a liquid that has a bit of sandy like diamond substance in it, and you put it on the screw head to prevent the driver from slipping while undoing screws.

This works well along with a brace and 1/4" socket and impact driver bit (No.2 Phillips).
(note: Not impact driver, leave that out of it).

As said earlier though, sounds more like seized/ corroded pistons rather than fluid. But replace it anyway.