robertj298 

My 86 Panasonic DX 5000 has developed a squeaking noise that I believe
is coming from the bottom bracket. It doesn't make the noise when coasting
or when it's on a stand. Only when pressure is applied to the pedals. It almost
sounds like squeaking rubber. The person I bought it from earlier this year
told me he had serviced all the bearings

Bigbus

A quick search says that bike came with a sealed bottom bracket set and Shimano 600 EX crank set. Have you tried wiggling a pedal side to side and see if the crank arm has any play in it? I doubt if the person you bought it from serviced the bottom bracket, but hey, I've been wrong before.

robertj298 

No play in the crank arm. I did notice one pedal spins more freely than the other.
Could this cause a squeaking noise and could that noise only occur under load?

Rolla

Take the pedals from another bike and put them on the bike that's squeaking. Remember that the left pedal is reverse threaded.

dsbrantjr

Clean the pedal and crankarm threads and grease one or the other before assembling and torqueing.

robertj298 

I changed the pedal on the one that was stiff, Still squeaks. I notice it squeaks
on the downstroke of both pedals.

Rolla

Pull the BB and inspect. You might just re-grease the threads and re-install, but if it's a cartridge unit, it's cheap and easy to replace.

andrewclaus

Of course, if the noise goes away when you stand up out of the saddle and pedal, it's the saddle or clamp. It's amazing how that noise telegraphs to the BB.

JohnDThompson 

Noises like this are notoriously difficult to track down. It could be the bottom bracket or pedals, but also could be shoe cleats, saddle rails, even handlebars or even something else entirely. Change one thing at a time until you can isolate the cause.

robertj298 

Tried this and still squeaks

robertj298 

I know this is supposed to have a sealed bottom bracket but the fittings on the outside look the same as my bikes that have the cup and cone.
Shouldn't it have a different fitting?

Bigbus

No, they'll look the same and both will use square taper cranks. Rolla might have offered the best suggestion with removing the bracket, inspect it for play and resistance and put a little grease on the threads before you re-install. Sometimes that little bit of friction in the threads can cause a noise. Good luck

2_i 

Usually, these are BB cups or arm bolts that are not tightened enough. The previous owner has not tightened them enough and you just follow the path, scared of overtightening.

robertj298 

I haven’t done anything to them yet

robertj298 

Could they be tightened too much? I have the axle and bearings removed cup seemed tightened pretty tight.
All the ones I relubed before I tightened them just enough so there was no no play in the axle but they
still turn freely

robertj298 

They were cup and cone. The grease was dirty so I thought I might as well
clean and regrease them.. The inside of the bottom bracket ,the axle and all
the bearings looked like new when cleaned up. Never had the inside of a
bottom bracket look so clean. Now I just have to regrease and put back together.

Rolla

Most BBs take between 30 and 50 Nm to be fully tightened, with some Campagnolo and Shimano units taking up to 70.

2_i 

I think psychologically it is difficult to go to the other side, but of course it is principally possible. You begin to destroy the threads then and shards of metal begin to come off. Yes, it begins to be loose then too, but the usual owner doing maintenance would not go there. The way you can test where you are is to ride and listen to the squeaking, while carrying a wrench. Then you tighten a bit more and listen do the squeaking. If yes, you are likely on the right track. Presumably a chainring that was removed and not put back tightly enough could generate a squeaking too. In that case the squeaking would depend on the ring you were on. Note that that legs can generate far greater forces than hands can. What might seem tight for the hands, might not be such for the legs.

robertj298 

That would be kind of a pain because you have to remove the crank to tighten the bottom bracket. I am stumped.
I would have swore it was the bottom bracket. It only makes the squeak when pressure is applied to the pedal it lets up until
pressure is applied to the other pedal .I've probably serviced 10 bottom brackets before and have never had any issue. I changed
both pedals also.

robertj298 

Problem solved. Of all the stupid things it was something simple. The rear wheel wasn't
locked in tight so when pressure was put on either pedal the wheel would move slightly
rubbing against either the brake or chain stay. It would move back when there was no
pressure. I feel so stupid lol

Crankycrank

We've probably all went through something like this before. Tracking down noises can be a real biotch and often nowhere near where you think its coming from.