The New And Improved Unofficial R65 Forum V2
Technical Discussion => BMW Technical Q&A, Primarily R65 => Topic started by: dflashman on July 15, 2013, 04:25:34 PM
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I have an '84 R65LS. Recently moved to CA and had the bike tuned and running like a top before I left TX. Took it out for a couple rides here and found it the other day with amber fluid pooled up in the right side of the hub and on the rim, rotor, and tires. The brake fluid meter by the lever is at max level though and it still seems to brake fine... The brake line also seems to be fine... could it be the caliper seals? Any input would be greatly appreciated, thanks!!
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I would check the entire brake system for leakage, if the brake fluid isn't low, the only other place for oil to come from, is the fork drain plugs .
They should have a copper or aluminum crush washer / seal on each drain plug, they sit in a machined 'well', if they are outside of this machined area, they need to be removed and filed down to fit the machined area .
The threads in the fork tube strip out quite easily, so be mindful of this if you attempt to tighten the drain plug !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
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Do check the fork fluid level as Bob suggested. Spec fork fluid is 7.5wt; thin enough to appear as hyd fluid on the floor puddle.
Since you mention all appears well with the brake system, I'd suggest wiping clean the fork lower, confirm fork drain screw is "snug" with correct washer and going for a ride. Check what's "wet" when you get home.
Give the puddle a sniff test. Hyd fluid has a certain "whang" to it.
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Or, sometimes I pour a little water onto a puddle if I think it might be brake fluid - if it is, you can often see things start to "clump".
It could be possible that a piston seal has let go, but I've also had the unfortunate experience of fork oil leaking from the bottom hex bolt that holds the slider to the damper rod assembly in the fork tube (this is hidden up above the axle at the bottom of the slider). When this happens, fork oil can drip down around the axle and onto the lower half of the rotor disc carrier and puddle there - and it will also centrifugally disperse it onto your rotor and ruin your brake pads, if it is in fact, fork oil. Most common fork oil is either clear or red, though the "official" BMW 7.5W stuff appears to now be purple in color...
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As Monte suggested, hydraulic fluid has a particular smell.
Aside from clumping in water, brake fluid will quickly strip most painted surfaces. If the paint on your front rim has suffered from the puddle, that would be a good indicator that the fluid is from your brakes.
Less common, but not out of the question, is making sure that the grease in your front wheel bearings hasn't separated and started leaking the thinner oils contained within. My grease gun in the garage has been dripping a tad bit o' amber fluid from its base in this last heat wave.
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...but the grease is pretty old and was separating in the tub to begin with...