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I'm hoping someone can offer a bit of sensible advice please. I've run into a problem with bleeding a new RX4+ caliper freshly attached to a Sram Rival lever. I've the Hope instruction sheet for the new caliper and followed it without too much problem. Dot throughout, new bottle freshly opened.
I set it up yesterday, seemed to be going smoothly but finished a wee bit spongy, so I left it overnight with an elastic band on the lever, bled it again this morning. syringes at both ends, plenty fluid, no bubbles appearing at either end when I push or draw fluid through. Yet there's now no resistance in the lever at all, the pistons aren't moving towards the blank pads that are in place. Very odd. Thoughts..?
Possibly take the caliper off and give it a shake to make sure any air sitting in a pocket out of the way of the bleeding route is getting dislodged. They are quite tricky to bleed. I have 3 sets, none of them feel the same as each other, think the levers used has quite an impact on feel. But, no resistance at the lever sounds like a large pocket of air somewhere that's compressing and giving zero resistance.
There is a hope video on YouTube which is good.
It took me a few goes on the back.
A bit of pulling on the caliper syringe to encourage air out seemed to to it for me.
I’ve had something similar with shimano levers and RX4s. I seem to remember detaching the caliper fro the frame and doing the pushy pully bit of the bleed at a couple of different angles helped.
I have Shimano RX4+.
I dropped the rear caliper off the frame and as I got to the adding new oil I pushed new oil all the way through, got shot of the duff stuff, then pulled new oil through and back a couple of times. Then continued on as per Hope’s video.
Used a bit more oil but the first time I’d done it on 3 or 4 year old calipers and worked perfectly.
Took a bit longer than I expected but not too bad
When they’re working they’re great, but they’re bloody horrible things to bleed in the Shimano version. So messy with the removable bleed grub screws rather then a port you put a tube over / sram bleeding edge. And the process in Shimano involved constantly taking the caliper syringe on and off. Gross.
I’ve gone back to Ultegra calipers and will just replace them every few years when the seals start micro leaking. Unless I get tempted to try the Magura flat mount 2 pot calipers they do.
What I’d say to you is really try lots of angles on the lever when you’re bleeding - I put my bike in a park tools stand and constantly changed the angle I was using. Meant I got all the air out.
That’s not the process I used @joebristol and it worked first time for me. I followed the Hope video and just added a flush through.
Maybe the Hope Shimano lees process is different to the SRAM one. Used a funnel thing at the lever.
I have come to the conclusion that the problem is more likely with the master cylinder than with the brake caliper. It seems to be jammed or disconnected somehow and now I cannot drive fluid up or down, plus pistons are unresponsive. Very odd. It's not an old Rival in terms of mileage and they are usually known for reliability. Puzzling.
Definitely a job to hand to your finest commercial bike mechanic. By all accounts fiddly to bleed, but my RX4+ are superior to the Ultegra callipers run in another bike by a considerable margin.
Shimano- I followed the vid exactly and it was fine, but it only shows the front.
For the rear I had the bike vertical, and rotated the bars in the stem as you use the pot thing, unscrewed the calliper and had that hanging down as well. Worked really well.
- Did the same as jkomo, bit fiddly but did the job.