If you don't want to read the whole story that's fine, just scroll down to the bottom where the problem is.

I just finished cleaning my chain for the start of the riding season and I decided to put on a power link. I grabbed my chain rivet tool to pop out two rivets and remove a small section to be replaced with the power link. Then I realized that the power link I had to put in was utter crap and could unlink with the slightest force in the wrong direction (say a pothole or something). I went to my local shop and bought a black SRAM powerlock, which the sales person advised me he uses himself on three different chains. I got home, and realized that the powerlock was reallly hard to lock-in. I put the link into the chain and tried to lock it into place using my hands but I couldn't apply enough force to lock it, I tried wrapping the chain around my legs and using my legs to do it, still nothing. I was amazed at how much force I was putting in but it wasn't locking. I can only get it to maybe 1/5 locked and I can't get it to travel the rest of the 4/5ths into place; I even lubed up each half of the link. I figure with some channellock pliers or something similar(which I don't own a pair of) that I will be able to get the link locked. I will be heading out one day to find some to add to my collection of tools.



The problem comes in when I tried to use the pair of pliers I do have. They aren't even quite large enough to get to both sides of the link halves. So I ran the chain through my drive train, put the halves into the eyes of the chain. Then I called in my room mate to hold my rear dérailleur into place to remove the tension from the chain. I got everything setup and applied some pressure, then the chain appeared to twist so I chose not to continue until I got big enough pliers for the job. Side note: I tried to lock the powerlock the way shown on youtube for unlocking it, but with the wrong kind of pliers.


Now the problem is that during this process of removing the tension, and before I applied any pressure to the link, their was a click or clink sound in the rear system. After I was done with my room mate I decided to investigate what the noise could have been and fix the chain so that it would go through the cage properly. After some investigation, I realized that was what sound must have been related to. The upper pulley isn't positioned correctly so that the chain touches both pulleys. It only touches the bottom pulley not the one labelled G pulley.


What I've done so far.
I took a look into my big blue book and found that there is a spring related to the cage positioning, I decided to take a look at it and opened it up but it turned out not to be the issue. I figured the noise was one of the prongs on one end of the spring snapping or shifting to a second hole which the blue book suggested there might be. I have a shimano 105 system on my bicycle. It does not have two holes and the spring did not break in any place. I am currently having trouble getting the spring and stuff back together to be able to remount the dérailleur onto my bike, the daylight is all but gone at this point and I find it hard to work on it with little light so I decided to post my woes online. If you have some tips on getting that bit back together I would appreciate it. I was able to get it rotated far enough, but I couldn't push the washer lock back under the threads on the bolt that goes through the middle of the spring. This is because I couldn't get the plate back on fully, there was a gap and I was unable to push it down. I figure I need to keep it twisted while I push it on all the way, and that was when it snapped all the way back around *sigh*

That was all I tried, so I have no clue why my 105 isn't positioned correctly.

Please give me some ideas to test out tomorrow afternoon when there is more light and I am done my errands.

Pictures, if you all want pictures please ask. If required or desired, I will collect some tomorrow. I will try and grab some of all the parts you mention, if I mentioned a part but didn't use the correct terminology and you need a reference as to what I am referring, again, I will collect a photo of it; just ask for one and quote the part in question.


Post-Solution Edit:
https://video.answers.com/how-to-inst...lleur-66770524
I saw one site refer to this pin as a p-screw but this video which basically shows you how to get at the spring calls it a p-knuckle. So to anybody who stumbles upon this thread with a similar issue, gl with you're p-part.

You've done so many things it's hard to tell what the problem might be. Possible cage was rotated past a stop, is routed incorrectly around the pulleys, or over part of the cage instead of going between the cage and the pulley. Need clear pics from side of derailleur, would not hurt to see video of rotating pulley cage. Bike part names can be easily found with a search rear derailleur diagram for example, also easy to google a pic of Shimano 105 rear derailleur.

A photo of the problem might help, though it sounds like you somehow threaded the chain through the RD wrong.

If you still want to lock the power link before going farther, pedal froward or backward so the power link is in the middle of the upper loop. (make sure it's the right power link first, because most problems closing these are because the link is too narrow for the chain, is 10s link, 9s chain) Once the link is half closed and in the upper loop, put the front wheel against a wall, or use both brakes so the bike can't roll and stand on the forward pedal to tension the upper loop and pull the link closed. (This is easier yet if you use the inner chainring for leverage (the rear sprocket doesn't matter either way).

Now as for the threading through the RD, starting from the lower loop, the chain goes around the back of the lower pulley, then around the front of the upper and on to the bottom of the cassette where it goes around the back, back-front-back forming a curvy M shape if you look sideways.

Oh my goodness, that is such a good idea. I had been racking my brain trying to figure out a way to apply leverage to the blasted thing. So simple. <3

I can assure you I acquired a 10s link.

As for leading the chain properly through the 105 I made sure to both look at another bike and my BBBook. Plus there is a little metal bit preventing me from leading it through the other way to the bottom pulley which means I can't lead it through the upper pulley for that purpose. Thanks for the quick replies, I am gonna get off of here tonight. I will post the pictures, hopefully, tomorrow afternoon; I will try to remember a video.

It might also be worth mentioning, it was threaded through the drive train properly before my mate touched the RD. After, not so much.

Cheers

Remember that not all 10 spd chains are alike and being off by brand or even a model within a brand may mean a small variance in inner width. Just like 6/7 speed chains can vary a lot from 7.0 - 7.4mm on outer width. This can make the application of the master link impossible to close if the main chain has an inner width too wide for the master link.

I got some pictures, I didn't grab a video because I feel that the pictures are adequate. There is very clearly a problem. Please note that the bicycle is upside down in these pictures as it is mounted into my work stand.

First off, look how much slack in the chain there is with no interaction with the bicycle on my part.


It seems to me that the upper pulley isn't far enough around its pivot point to make contact with the chain.


Here is a, perhaps clearer, picture of of just the RD/wheel.
Upper pulley on the left of course, lower on the right.

That middle picture shows you did not put the chain around the pulley pair right.



trouble shooting over the internet is easy to ask questions.

and hard to answer, what is simple, if in your hand ..

Spring? will it wind up and stay that way..?

Actually, I did.. Look at it again and flip the image in your mind. The chain makes contact with that pulley on the side closest to the cogs.

Edit: There is literally no other way to guide the chain through. There are metal tabs on the cage preventing you from leading it through the wrong way.

Actually, the problem I see in the picture is the rear derailleur itself; it's 'folded' forward, rather than toward the back, as it should be. A picture showing the entire run of chain (from the crank all the way back) would be beneficial, but I'm wondering how the derailleur got INTO that position in the first place. It's not sitting right, by any means.

The chain looks right, the RD looks wrong. You've lost tension somewhere in the RD. Look at the exploded view in Shimano tech docs to see if it gives you an idea where the problem is.

I put all the information I can provide relating to how the RD came to be in this state of affairs in my OP.

Here is a better look, in my opinion, of the RD.


Here is that image you requested of the entire drive train.

Where you are pushing back on the RD cage, the spring should be pulling it back. The earlier picture where the RD cage is basically laying on the cassette with no chain shows you've lost all spring tension.

It is threaded correctly, but if the chain is that short, it's way too short. This is what it usually looks like on the big, big combination.

Also if the RD isn't trying to return the lower pulley down and back (clockwise) it's because the spring has unwound past the stop. Remove the chain, and wind the RD cage one turn counterclockwise to set the spring tension.

There's supposed to be a stop to keep the cage from rotating more than 1/2 turn and unwinding, but sometimes these break off.

BTW- for futire reference, please turn your photo's right side up and from the right so the bike appears the way we're used to seeing it.

dude, your RD is clearly upside-down. My guess is you put the wheel back on without the chain on and let the RD rotate around past the dropouts. Its not touching the B-screw stop

It appears that you took the spring out of the RD, if I read your original post. And you failed to put it back in place correctly. There is insufficient chain tension with that sag in your picture. This can only mean your pulley arm on the RD has insufficient spring force pulling on it. And that's why your RD is in that position. You'll need to remove the bolt that holds down the lever arm, and get that spring tension wound up. This isn't always easy and requires some finesse to get the spring tabs to insert into the correct holes. The main body slant parallelogram should be somewhat lined up with the chainstay with label oriented likewise. It's clear that your main RD body is completely in the wrong orientation. It means you could not have the correct RD pulley arm spring tension correct unless your chain was, as FB noted, way too short. But then there would be zero sag in the chain. You have sag. So the chain is not under tension. That's likely your problem.

I always enjoy the replies that appear to be based on a single post I made. *looks at redlude*

@CACycling I think you're right, I decided to remove the pulleys and clean the cage and all those bits and pieces. Whilst doing so I found another location that looks similar to where I investigated the spring I mentioned earlier. This one has two holes though, and it also doesn't appear to have any spring catch poking through either of them. So that would fit the bill for losing ALL spring tension. I can't see any obvious way of opening this spring cylinder to gaze upon the spring itself though. Any tips or maybe just telling me what this spring is called will probably help speed me up in my research.

The problem arose before removing that spring, and I put that spring back in earlier today.

I want to have a second pair of eyes look at this before I potentially increase the water level in my sea of woe.

If I am reading this diagram correctly, it appears that I need to remove #8 to remove the remaining side of the pulley cage, which will garner me access to the spring inside.

https://www.shimano.com/media/techdoc...9830753822.pdf

However this screw appears to be missing altogether, so.. argh!

help me? :S

'Float Check' that one in your sea of woes..

Go On.. .. stop fussing over dead components.. Buy a new RD and replace the broken one.


Shimano is notorious about being poor on small parts
you will have a hard time finding a replacement spring, if it is broken.

If the problem arose before removing the spring, then that would indicate the spring had already failed and it is still inserted in there and not doing its job. So you need to go re-examine it and see if it's in the right holes, or if it's cracked. The RD has an unmistakable orientation. If you put back the spring and the pulley arm isn't tight to the main body and does not require strong fingers to pull down, then the spring is not working for you and that's still your problem. The chain is a secondary issue.

I'm not saying that the chain might not have caused the issue, because cross chaining with too short of a chain can bust up RDs and snap the spring. So you may need to fix multiple issues: a) you cross chaining, b) lengthen the chain, c) RD pulley arm spring.

The mounting bolt spring, which you are talking about, works 100% and is not broken. The cage pivot spring however, I believe is either broken or missing a vital screw. I may just take the thing in to my bike shop to both compare with the 105RDs they've got and for any advice they can provide. I am sure hands on diagnostics is a lot easier than over the line.

@Fietsbob, I appreciate that you are helping make this a lively thread and thank you for that.. but if you aren't going to help actually diagnose and or repair/replace what the problem is then please go tell somebody else to go out and buy a new derailleur. kthx

BUT.. Repair Turnaround in mind.. (I worked in shops) It will be back on the road right away ,
if the other one is reparable , once the thing is perhaps fixed,

the the kid will have a spare.. the replacement doesnt even have to be 105 ./.

It's fine you took the pic with the bike upside down - it would be considerate if you flipped the photo before posting.

You managed to unspring the derailleur, which can be done without the spring breaking or being removed, but could be from the end of the spring that inserts into the derailleur body breaking. Yes, compare to a working 105 and you should be able to see your error, or get someone at the shop to show you how you went wrong.

Yes, somebody already mentioned that I should have done that. I didn't directly reply to that, I don't recall at least, so I will now. If I need to post any pictures in the future I will either flip the bike around in the stand and kneel, or I will be sure to rotate the pictures. Also, I apologize for not having though to do so originally.

I know where I went wrong, asking my room mate to put tension on the derailleur to remove tension from the chain.

Thank you.

No, I meant exactly what happened. Asking your roomie to put tension was not the cause, it was something he did during that process. Until you know what was done you can't undo it.