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Post by Diego the toe clipper on Jun 6, 2021 8:34:45 GMT
WD 40 ? On discs?
Should have gone and bought some brake cleaner. You're going to need it now anyway.
But if they are seized solid I reckon you really need to free them off before thinking about spending on new discs.
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Post by pantah on Jun 6, 2021 8:39:44 GMT
WD 40 ? On discs? Should have gone and bought some brake cleaner. You're going to need it now anyway. But if they are seized solid I reckon you really need to free them off before thinking about spending on new discs. Brake cleaner is alcohol based and won't unseize. Once the wd40 has done it's job the brake cleaner can clean things up. Simples. |
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Post by elnoodle the reasonable on Jun 6, 2021 9:51:04 GMT
I took the calipers off so as not to contaminate the pads. Not too worried about getting lubricant on the discs as I'll clean them up with brake cleaner after.
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Post by elnoodle the reasonable on Jun 30, 2021 22:38:09 GMT
I've gone nuclear on this. New discs, pads (obvs) and Hel braided hoses. I'm certain that at least one of the discs is warped after putting it all back together and riding it. It's a fucking death trap as it is so I've splashed the big bucks.
I went for EBC discs as they were half the price of Brembos. Should be perfectly adequate for the road.
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Post by elnoodle the reasonable on Jul 18, 2021 17:07:10 GMT
Finally got round to doing the work. Took the front wheel off and one of the bearings had collapsed. Fuck all to do with the discs.
Will need to get bearings this week. I could return the new discs but I might as well just fit them. It will need new discs soon enough anyway.
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Post by armstrongracer on Jul 18, 2021 22:56:57 GMT
Sooo.. you mistook collapsed wheel bearings for shot discs. Fuck me noodle, you must have the sensitivity of a National Health Johnny.
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Post by elnoodle the reasonable on Jul 18, 2021 23:18:35 GMT
Sooo.. you mistook collapsed wheel bearings for shot discs. Fuck me noodle, you must have the sensitivity of a National Health Johnny. Yup. I've only been riding bikes for 37 years. I'm still learning. |
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Post by elnoodle the reasonable on Jul 19, 2021 19:29:23 GMT
Got new bearings and fitted them with the new discs. Thought I'd clean up the caliper pistons before fitting the Hel brake hoses. One of the pistons was quite badly corroded and dragged the dust seal out.
So, caliper rebuild it is. Doesn't look like the calipers split so fuck knows how you're meant to get the seals out.
A caliper piston kit is £170 on EBay. At this rate I'd have been cheaper just buying another fucking fireblade.
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Post by Diego the toe clipper on Jul 20, 2021 6:58:46 GMT
Never rebuilt monoblock calpiers, but I understand it to be a total cunt of a job. Do you have an air line to blow the pistons out?
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Post by elnoodle the reasonable on Jul 20, 2021 8:00:00 GMT
Never rebuilt monoblock calpiers, but I understand it to be a total cunt of a job. Do you have an air line to blow the pistons out? No. Not sure how I'm going to do it. If I'm replacing the pistons then I don't mind mangling the old ones with mole grips getting them out. I'm more concerned about the seals tbh. |
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Post by mekon on Jul 20, 2021 8:36:00 GMT
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Post by elnoodle the reasonable on Jul 21, 2021 12:33:54 GMT
Not Brembos but close enough. Some good tips there. Ordered the rebuild kit from Powerhouse. They do the rebuilds for £57 per caliper. I may well regret not taking them up on this. |
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Post by elnoodle the reasonable on Jul 23, 2021 15:45:24 GMT
Rebuild kit arrived and the first thing I noticed was that the new pistons are a fair bit heavier than the originals. The new ones are stainless steel, I think the old ones might be aluminum with a chrome (or similar) coating. It's the coating that has deteriorated.
Since I'm only using it on the road, I really don't mind a few extra grams of unsprung weight if it means the caliper internals will last longer and be more reliable. The brakes have always been the weakest part of this bike and I'm expecting a considerable improvement when it's all done.
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Post by elnoodle the reasonable on Jul 23, 2021 22:07:53 GMT
All done. I've left the lever bungeed to the bar overnight so any remaining air bubbles will rise through the system.
The caliper rebuild was a fairly shitty job. I ended up getting a car mechanic mate to help and we managed it between us. All in I've spunked £500 on my brakes when the original problem was £18 wheel bearings.
However, the calipers needed a full rebuild which I only realised in the course of replacing the discs and braided hoses are always a sensible upgrade. So the only "unnecessary" expediture was the discs but they would have needed replacing before long anyway and the new discs look much better so I've no regrets there.
There are a couple of lessons learned:
Properly diagnose the problem. I thought I had warped discs because the pads were being pushed out when in reality I had fucked bearings which meant the wheel had some lateral movement and this was pushing the pads out.
The calipers have different diameter pistons and there is no more than a bawhair in it (30mm and 32mm). You wouldn't notice without sizing them against each other. It would have saved a lot of grief if I'd known/checked this beforehand.
Bleeding was a total prick. I ended up sucking the fluid through with a syringe. My next heroin hit will be interesting.
I bought the discs, pads and Hel hoses from sportsbikeshop.co.uk and the caliper rebuild kit from Powerhouse. I got great service/prices from both.
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Post by bella on Jul 24, 2021 9:34:01 GMT
2mm !, that's asking for trouble, You'd think they would have the sense to make pistons identical sized to lessen the risk of mistakes, obviously unless there was a good difference in size.
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