82 XJ750 brake question

I'm rebuilding this bike and I've got a really stupid question about the brakes. How do I get the pad retaining pin out? I've unscrewed it about a 1/4" but that's about all it wants to unscrew on either side. Am I just supposed to drive it out? I tried a few little taps with a hammer but it didn't seem to do anything. I checked in a Haynes manual but it didn't elaborate on how the pin comes out

Thanks

 

Hi and welcome to XJBikes.

I did mine not long ago. Push the pins back in. The pins are exposed on the inside where they go through the pads. I had to give everything a good clean, then use WD40 on the pins then drive them out, (hammer and drift) they were tight as. When I got the pins out I cleaned them and they slid in OK on re assembilly.

 

Welcome to you bittwiddler, let's see what we can do to get you moving. I've just pulled apart my 82 750 and the pins are secured with cotter pins on the inboard side of the caliper (the side you can't easily see). If you can, pull the caliper cover off (it is that flimsy plastic thing on top held in with a philips screw) and peek at the back side of the caliper. You should see the pins there. If they are the originals, you should be able to unhook them and pull them out easily. Otherwise, you might have to pull the caliper (14mm bolts X 2) and go at it that way. Best of luck, be sure to polish them and lube them up with brake caliper grease (a VERY thin film) when re-assembling.
I had issues with my originals as well, they were darn near welded to the caliper body. I turned some new ones out of stainless steel and they look spiffy!

 

Hey Bit......yes, that pad-retainer pin just screws out, it gets really siezed in there after all those years....just lube it up greatly and whack it out with a punch (be gentle, of course, while you're whacking at it....). It'll come out. And make sure you polish it up really well before putting it back in, some anti-size on the threads wouldn't be a pad idea at all.

Robert, I believe he has a regular garden-variety 750 Maxim, not a Seca, so this style caliper does not use the cottter pins.

 

:wink:

No cotters on my Seca, pins have a thread at "outside" end and a allen head to undo.

 

Yeah this is a Maxim. I don't see any pins but it is a bit hard to see in there - especially with the gunk that's built up.

Does the cotter pin screw all the way out? When I look into the caliper it doesn't look threaded there so I would guess it screws out about 1/4" like it did and then you can just pull it out. Mine, of course, doesn't want to pull out but I was afraid to give it a good whack

 

No, it won't screw all the way. The threads in the caliper body do not extend all the way to the "outer" edge of the bore, so they pin will unscrew "completely" and still not have the threaded part of the PIN all the way out of the hole. Just make sure it's all the way unthreaded before you start hitting on it, though! And I would recommend that you first SCREW IT BACK IN, then "polish" the pin with some fine sandpaper (to remove any burrs, nicks, etc. on the smooth part of the pin shaft), lube the dog-snot out of the (now smoother) pin shaft and spray lubricant into the pin bore hole; if you want to get all fancy and stuff, stick the entire caliper in the freezer for a few hours and then CAREFULLY and GENTLY heat the caliper body area with a pencil torch or heat gun, etc. (but leave the pin itself cold/frozen and thus in a "shrunken" condition) and then try to unscrew/hammer out/extract the pin.

Trust me, it's tough to get it out. And not a bad idea to run a clean-up tap through that threaded hole before you re-assemble. And a very fine file through the non-threaded hole (where the end of the pin enters) on the opposite side of the caliper.

In fact, since these calipers are such an odd design (if I recall, they're unique to this one year and model!), it would do your soul good to clean-up/re-tap every threaded hole, and to make sure that you really, REALLY clean the dust seal and fluid seal grooves/lands in the caliper piston bore, as well as micro-polish (as much as possible) the piston. Make sure you use some pure silicone grease or brake assembly lube when you install those seals/piston. Give the piston bore an good, quick swipe with a brake cylinder hone. PRAY that the "double o-ring" that lives on the end of the large slider pin (on the caliper retainer plate) is in good shape, cause you ain't finding that puppy anywhere! And clean the bores in the caliper really well that both that large and small slider pin fits into. Replace the rubber boots that seal those slider pins if they're torn.....but make sure you keep the metal retaining disc for those boots, as they do NOT come with the replacement boots (I sell those boots, and they aren't cheap!) and otherwise those retaining rings are unobtanium. Lube those slider pin bores very well---after you've cleaned them completely and incredibly well----because if the slider pins can't move in-and-out VERY freely, the caliper gets stuck or cocked and that's a whole nightmare in and of itself. Make sure the air-pressure-relief holes in the slider pins are clear of gunk so that the pins can move freely.

Good luck, Jim. The Secretary will disavow any knowledge of your existence should you fail in your mission. And this message will self-destruct after 3 seconds............

 

Ok, sorry, I didn't get enough info from the first post to "savy" the type of bike. I also have those stupid screw in calipers, lousy design if you ask me. Took oodles of soaking and impact driving before I had to use the eazy-out method to remove them. I'm not planning on using these calipers again, I'm upgrading. I'll see if we can't turn some new pins out of stainless.
Glad someone came to the rescue (thats you Chacal, your my ace-in-the-hole).
Best of luck Bitt!

 

Stainless pins sound like a really swell idea!

 

Thanks for all the tips. I'll work at them to get them back into good shape.

Any recommendations on how to polish the pin if I screw it back in with the brake pads still in there? Or did you mean once I get it out the first time to remove the pads?

 

Before you take it out. Since the pad "ears" ride on that pin, the pin tends to get a bit scarred over time. If you can screw the pin out a bit---enough to drop the pads off, then you can polish it with a strip of crocous cloth or file it gently to remove any scars or ridges.....so they won't eat into the threads as you further extract the pin through the threaded part of the bore.

If the pin seems to be pretty smooth already, with no protruding grooves or ridges or serious rust, then you can bypass that step.

 

I'll try. Right now I can see a gap where the pin has come out from the other side but about all I could slip past it is a sheet of paper. I dribbled a little brake fluid in there last night and I'll go down shortly and see if it will move some more

Thanks for all the help. At least now I know there isn't something like a pin in there that's preventing them from moving

 

Once you get the pin out it can be polished by chucking it in a drill spin the pin and use a strip of sand cloth till shiny new.

 

Dripping some brake fluid on the pins and letting it soak through overnight definitely seemed to help. I gave them a good tap and they moved a half inch - far enough for me to get the pads out. I then tapped them back in and smoothed down some of the minor scars with them in there. They then came out relatively easily. I cleaned a lot of what I could get to and they went back together easily enough. I will clean the pistons and everything like Chacal said once I can verify they're going to work alright and can dig up some info on what all needs to be done

Of course something had to go wrong - one of the bleed valves was frozen and snapped right off when I tried to loosen it. I'll have to try an ezout to get it out. Is this a a Yamaha only part? It looks similar to the Honda ones I have on another bike and there isn't a convenient Yamaha dealer around

 

Robert - I too would be interested in stainless pins if you do decide to make them

You mention upgrading the calipers - is there another model that would bolt right on in place of these? What are the advantages of this other model? After all this would be an opportune time to put a different set on

 

I'll let you know. The pin setup you have also applies to the 82XJ650LH front end I have so I'll have to pull it out and see if the 750 Seca calipers will work. I'll get back to you, got class today and tomorrow so Wednesday is the earliest you'll hear from me on this.

 

No hurry - I have a get this bleed screw out anyway

 

What chacal says is vitally important. Treat this job as a restoration. Take the Caliper off the bike and separate the Mount from the caliper.

Clean the Bore and the Travel Rod and Install some new O-rings. That Travel Rod is the Key to having the Caliper function well. You should clean the "Piston" having the two O-rings on it and but a nice new finish on it with 800 and 1000 Finishing paper.

Clean-out the Bore in which it travels. Roll-up some 800 Paper and rotate it the bore and spray-out the grunge in there.

Use some waterproof grease when you re-assemble the parts. The grease will make it difficult to insert the Piston-like part back into the Cylinder it travels in ... but, you can "Burp" out the air by squeezing it together and pulling it apart a little bit while you are re-inserting the Travel Rod.

New O-rings are going to make a nice seal and Keep out moisture.
Make sure the Dust boot fits around both half and you'll have done some maintenance that should last for a long time.