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my hope m4 brake lever keeps staying in. once I apply the brakes and remove the pressure on the lever it stays in until I press the lever a few more times then it pops out again.
I've remove the lever & cleaned all the gunk off then bleed the system. but the problems still there.
any advice?
sounds like a seal problem in the lever (master cylinder). You can get new seal kits, but I found it a right pain getting the main pushrod seal back in the cylinder (the lip seal has to go past a step in the bore). Local bike shop helped out for nothing
Could be the lever pivot bolt tightened a little too much, or as mentioned above, a seal sticking/swollen. Have you been using spray lube around the lever pivot, some are mineral based and will attack the seals, if so then a new seal kit and extremely thorough cleaning will be required.
I had something very similar where the lever would not return. The brake itself still worked ok but the lever was floppy until the biting point of the brake.
One of [url= http://www.wiggle.co.uk/hope-disc-brake-complete-seal-kit/?utm_source=google&utm_medium=base&utm_campaign=products ]these [/url]seal kits should do the job.
[url= http://www.singletrackworld.com/forum/topic/mono-m4-lever-not-returning-properly-loose-feel ]Here's[/url] a thread from a while back with all the stw knowledge you will need.
Once you have dismanteled the lever [url= http://www.singletrackworld.com/forum/topic/removing-seals-on-hope-mini-lever-master-cylinder ]this[/url] thread will come in handy. Also replace the little spring inside the lever, the part number is [url= http://www.ukbikestore.co.uk/product/222/hbsp110/mini-spring---master-cylinder.html ]HBSP110[/url].
Its not a hard job and the lever will fell like new after.
could be the overtightened lever pivot. I found the one master cylinder I rebuilt easy to do. Just get the seals in the right way round.
I had the same on my Mini's and on stripdown I found the piston had corroded inside the lever
Bloody piston cost me £7 well miffedd off after a mere 8 years use
Bloody piston cost me £7 well miffedd off after a mere 8 years use
That's the thing with hope's, high maintenance costs. 😉 I replaced all the lever internals and the caliper pistons and seals after 6 years of abuse and the things are as good as new.