Have a 1990 240DL. I changed the read brake pads with anti-squeal compound on all contact surfaces (except the pad surfaces, of course). Attempted to change the front pads on the right front wheel, but the new pads wouldn't go in, so I put the old pads back in. Did nothing with the left front wheel.

With the first drive, the "brake failure" light came on, although I had sufficient braking power and didn't notice any sponginess or little loss in braking power. Then after about 7-10 miles, noticed brake fluid leaking from all 4 wheels, but it could have started earlier without me noticing.

The brake fluid level in the reservoir is still very high and does not appear to have dropped. It only seems to leak while driving. While parked, there is no leakage.

Brake system recent service history (current mileage: 194,000):
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04/1999 131,000 mi Replaced master cylinder, brake junction box, all pads.
1998 120,000 Replaced all rotors and pads.

What should I do about the leaking?

Thanks.