[Closed] Can I replace a 7.5uF capacitor with a 8uF capacitor

Probably. The rating will have been played with to give the best phase offset to start the motor. This will give a slight different shift so may still run ok but if it's a start capacitor it may have slightly less torque at start or if it's a run capacitor in addition it may be a little less efficient and the motor may run slightly hotter. This may reduce the life of the motor.

If it's all you can get I would give it a goo personally.

Thanks for the info - good to know. I've finally found a 7.5 that's available within a reasonable timescale so going with the proper job.

Check what Marty McFly thinks about flux capacitors

The lower voltage rating may be an issue? If they have specced parts to be a close to spec as possible (for cheapness) then the original 420v cap may not be that generous.

Thos is good timing.

I'm getting the hummy hummy no turny turny which i assume is the capacitor as the drum is still stiff.

Well just for completeness here's the update:
£6 (delivered) capacitor arrived this morning. Fitted in a couple of mins as I'd already taken the top and side off the drier and vacuumed out the very considerable amount of dust and fluff that was inside after about 15 years of use.
Put it all back together and it's running like a champ!!

Plus I've got 3 screws left over...... doh!

Those screws limit it to 1.20 GW. You don't want it to go any higher.