July 6, 201313 yr Please can someone give me some advice or reason as to why the hell my 4 pot AJP caliper will not seal when new seals and pots have been fitted. Cleaned all componets.....grooves clean ...seals in ....pressed pots into caliper by hand..with a little help with spray oil.... All together back on bike and still p****** fluid out when pulling brake...HELP...this is my second set......and £50 quid in all ready.... Any advice appreciated....
July 6, 201313 yr Hi there, firstly don't use oil of any kind on brake seals. Moisten the seal with brake fluid before fitting it into the groove. If it is fitted dry it sometimes does not bed in properly. Lubricate the piston with brake fluid, red rubber grease or silicone grease and work it in very very carefully. It is easy to damage the seal lip if it has to be forced in. You need to strip it all out again and inspect everything under a magnifying glass.
July 7, 201313 yr It would be difficult to get the pistons in had you done so but could you have fitted the seals the wrong way round? There's a very slight taper on them so that they seal under pressure and grip the piston to pull it back in slightly as they return to their original shape when you release the lever. Edited July 7, 201313 yr by 2stroke4stroke
July 7, 201313 yr Author Thanks for the info...will remove clean, inspect and try again.....used lots of (wd40) to get them in both times.......what a numpty Disco
July 7, 201313 yr Assuming the seals are in correctly, you may have hit upon one of the more challenging aspects of modern life. As companies try and protect proprietary formulas, they tend to use every legal means to limit access to exactly what's in all these wonderful concoctions. Take air fresheners for instance. If you look at the back of the can, most of the time it'll just list propellent (often propane) and "fragrance". Sounds plenty harmless huh? However when you look at the MSDS sheet for some of these products, the "fragrance" is a concotion of chemicals, often carcinogenic, and rarely something you'd willing spray in kid's bedroom if you actually knew what was in the damn stuff. Although WD40's website lists the product as being safe for use on rubber, it's been the experiance of many that it's really tough on neoprene and several other synthetics causing swelling and disintegration. Even though you need to use protective gloves, you'll probably find the best product for assembling brakes is the actual brake fluid recommended (in the case of a Beta DOT3).
July 7, 201313 yr Agreed, spray WD 40 on a balloon and leave it overnight, see what it looks like tomorrow
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