I'm in the process of renovating a pair of RL 140s. and will share what I have learned so far in response to your ?s concerning disassembly and woofer refoaming.
Disassembly:
Set speaker face down on a flat surface protecting the forward edges it will be resting on. The rear of the speaker is facing up. All screws to be removed are Phillips head. Near the center are two recessed bars that hold the straps on, remove the screw from the center of each bar. My straps were gone, but it appears that as the bar is removed it would loosen the strap allowing the bar/strap to be moved sideways and laid over out of the way. The straps are attached to the bars by screws the removal of which would allow the straps to be removed without raising the speaker.
Remove the 2 screws in the recess the bars came out of. Remove the screw in the central recess. The metal mounting plate around the central recess may be left in place. Remove all screws that are found in the circular openings around the periphery of the speaker and in the center of each side. I'm away from my 140s, but I believe the count is 10 screws (not counting those under the bars and in central recess) per side.
The back is now ready to be removed. The gap between the redline and the speaker back is the seperation area. I used my fingers to apply pressure to raise the back up and away from the rest of the speaker. Be patient, working your way around the perimeter to raise the back as evenly as possible. There is a foam gasket between back and body of the speaker, take care not to tear it. Once the back is clear, the leads to the external connection jack must be dealt with. They are barely long enough to raise the back far enough to disconnect them. Mark the terminals, then pull the leads (spade type connector) from the jacks on the speaker back, which can now be lifted clear. Make note of the wrapped fiberglass blocks positions to enable correct relocating when reassembling. All components of the speaker are now accessible.
Woofer surround replacement:
I'm not a complete novice nor an expert as the woofers from my RL 140s were the 3rd & 4th pairs of drivers I have replaced foam surrounds on. Yes the clearances are tight, and I shimmed the voice coil/cone (also on the first 2 pair of woofers I did) to ensure success. I am quite pleased with the results in all cases and the RL 140 woofers sound very good. I have not played them much, however, as I was dissiapointed to find one tweeter of only approx. 50% output. I'm in the process of dealing with that problem, but that's another thread.