1985(86) XJ700 Caliper Rebuild

Initially, I thought I’d get through the process and I’d post my entire rebuild from beginning to end. Then I thought it’s better that I post in stages and consider the thoughts of the good folks here as I go… Especially since I have never done this before and honestly don’t know what I’m doing! Today is the teardown and clean up of my newly acquired eBay XJ700 front calipers. I was going to just rebuild the ones I have on the bike now, but then I can’t ride while this gets done.

Here we have our suspects. Relatively clean on the outside… they came packed nicely, though they were rolling around in their own fluids… Both for 12 bucks (plus shipping)! How can you beat that?





After pulling the pins and pads I used compressed air to get things moving… The 700 has a two piston caliper, so the air will inevitably push one and not the other. When the two pistons come together, you’re done.




Grab a 14mm wrench and remove the two bolts holding the two halves of the caliper together.

 

When you take the two halves apart, the piston that did most of the moving should come out pretty easy… Mine took nearly no effort…




Now you have to deal with the other half. The two halves of the caliper share the brake fluid through two fluid transfer ports. For the second half of the caliper, you’ll have to plug up one side (I used a punch) and force air into the other side. YOU NEED TO COVER THAT PISTON when you do this. If you don’t, you’ll get really familiar with that piston really fast! The rag I used is not there in the picture so you see what is going on. Give it a good shot of air. The pop of the piston out of the bore was more satisfying than a champagne cork on new years eve! Again… keep it covered when you do this…



Look at all that good stuff that was floating around in your brake fluid!




Drain off your fluid and pull the dust seals…

 

Then pull your pressure seals…




Here you can see your fluid transfer ports… make sure you clean these as well… Pull the rubber fluid transfer port seals off too… you’ll want to replace them… At this point I gave the calipers a good scrubbing with brake cleaner, then rinse with water, then more brake cleaner, then more water, etc...




Now it’s bath time… I used good concentrated dish liquid and soaked all of my parts in it with hot water… I was amazed at how it really did cut though the brake dust grime that the heavier chemicals didn’t get! Scrub thoroughly and rinse!




Clean and ready for rebuild. Keep in mind, you'll have to do two of these for the XJ700. Len @ XJ4EVER (top right hand corner of every page if you don't know who I'm talking about) has already confirmed that the new seals are on their way, along with my much needed master cylinder rebuild kit…


Let me know what you think I should be looking out for as I put these things back together. I’ll update the thread with pics when I get it done…

Thanks!

 

Great post

 

Ordered on and Shipped from Atlanta, GA on Jan 30th. Received in NY on Feb 1st. That's the definition of fast. Thank You Len.

Now, any advice on the application of grease and reinstall/assembly? I feel like this is one of those "not too much/not too little" amount of grease situations to minimize the chance of the grease and brake fluid mixing.

Thoughts from those who have trampled this path before?

 

Great post! I'm about to go through the same process. I look forward to any experienced users comments on grease and re-assembly.

 

That is correct........you want a thin smear on anything, minimize build-up, it really won't contaminate the brake fluid, it's designed to be used with it.

 

Any when you say anything, do you mean everything? All three (dust, pressure and fluid transfer) get the grease?
Also, Seems like the bolts holding the two halves together will "bottom out" when tightened. Is this the case or is there a torque spec?
I'm assuming that I should use thread lock as well?

 

Yes. It doesn't hurt to put a little bit on the slider pins, too.

They won't, and we've never seen a torque spec either, but you remember how hard they were to break loose? That's how hard you'll need to tighten them, too! Semi-permanent (purple) thread-lock won't hurt, but should not be necessary.

 

Good point... Indeed I had to put them in an open vice to give me the leverage needed to break 'em loose.

 

I now have more to share...

Now that we’re “zestfully clean" and rebuild parts are in house, let’s put things back together…
After a thorough clean up, I gave the pistons one last buff and polish with Mother’s Mag and wheel polish. They shined up real nice!



Snip the grease packet and squeeze a small amount on your favorite finger!



Give the pressure seal (the thicker of the two provided) a thin coat of the grease and send it home into the larger of the two grooves in the piston bore.



Then do the same for the dust seal! It goes in the thinner groove.

 

Your fresh seals should look something like this in their new home…



Now it’s time to send your piston home. With even pressure on either side, she should slide right in. Be careful not to scratch it on the edges of the bore.



Now do the same with the other half of your caliper…. once that is done, it is time to address your fluid transfer seals.

Give your fluid transfer seal a thin slather of grease like you did the others. You’ll notice that there is a recess on one half of the caliper, but not the other. Seat the seal in the recessed groove. There are two so you’ll have to do both…



On the other half of your caliper, you’ll notice the matching surface is flat. I gave that spot where the two come together a touch of grease as well.

 

Now sandwich them together and put some Removable Loctight on the threads of the bolts. Don’t use the HARD STUFF! the blue Loctight should suffice.



When both of your bolts are put into place “finger tight” you’ll notice that there is still a gap between your halves. That’s because the transfer seals are there…



I used an open vice with a rag in it to give me the leverage needed to wrench down on the two bolts. I went back and forth from one bolt to the other until the transfer seals begged for mercy.



When she’s good and tight the gap should be gone and the residual grease should be satisfyingly squeezed out!

 

Now… do it all over again because you have two front calipers!

Well that’s it for now. Here are the rebuilt specimens. I’m working on the Master cylinder right now and have documented things in pictures so far. I’ll be adding it to this thread as well. The plan is to assemble the entire front brake system at Hogfiddles’ Central New York Carb Clinic this June… complete with new Stainless Steel braided lines. I’ll update the string as more happens…

 

This an excellent thread, meticulously written and photographed.

 

Thank you @Maxim-X. I'm learning as I go with the help of those here. If anyone should see a problem with what I've said (procedure/steps/sequence, etc.) please let us know here. I thought about what I would have wanted to see BEFORE I started the job... then took those pictures. Much thanks to @hogfiddles and @chacal for their support on and off the forum.

I'm done rebuilding the master cylinder now. I'm thinking I'll post that sequence here in this thread as well. In June after the carb clinic, I'll have the entire front brake system assembled and back on the bike... That will close this chapter!

 

Looking real good!!

 

when your done with the brake system maybe len will consider it for a pdf on his how to's

 

I'd be happy to format it as a PDF if he feels that it is worthy!

 

Would be happy to!

 

Post Carb Clinic Additions… The final assembly was done under Hogfiddle’s watchful eye.
I figure I should keep all of this together as this is the final piece of front brake rebuild for the XJ700n system. Like the front calipers, I purchased a used MC from eBay for the rebuild. Here you have the replacement unit with it’s guts out. There was a dry rotted dust boot and a circlip that you’ll have to muscle out… more on what that looks like (on the re install) down the thread. Nice and crusty!




After removal of the insides, I did my best to really buff the bore as much as possible, picked out the majority of the fluid level viewing window, taped up the openings and bead blasted it in a cabinet.




After the blasting, I got in there and picked out the remainder of the window. The yellowish clear ring was the window edge, then there was the metal plate with the slots and the o-ring that holds it all together. You have to clean the groove really well before install of the new window. Good time to do it now… use acetone.. there was “gummy” bits and window residue in there…




Next another wipe down with acetone… I think it’s always a good idea to use gloves. What is the sense in having your skin come in contact with chemicals anyway? Besides, the gloves keep you from transferring your oils back on to your prepped MC just prior to paint.




After Paint! The screws look bad… but we get new ones anyway!




Now for the good stuff… A complete MC rebuild kit from Len @ XJ4Ever! Get one. You won’t regret it.




You’ll have to cut down the tip of the applicator on the RTV tube. I nipped off the very tippy end of it first.



Then I whittled it down to a point. You want the thinnest “squeeze” of RTV possible. You’re about to attempt something difficult!


You’ll want to set yourself for as much accuracy as possible. That sight window groove is small. The RTV is sticky and hard to work with. You’re also working with a tiny circle glass window. You want to do your best to get it right the first time. If you get the RTV where it shouldn’t be… You’ll have to clean things up and start over. You want to keep your glass clear… and you just painted that shiny new MC… remember?



Now put the RTV in… Not too much… but not too little either. That bead of RTV has an important job to do.




Once you put your RTV in, make sure your fingers are clean of any RTV (or perspiration, anxiety, cheese doodle dust, etc.) and send that window home.




After the glass was set, I put a second application of RTV on the outside. It’s REALLY hard to get that stuff smooth when you’re working in such a small area and in such small quantities. It’s a bit “lumpy” for my liking, but it is strong. Once done… Leave it a day or so to really set up permanently.




Now for the guts…
Take your new spring and plunger gasket… assemble and slather on some of the included assembly grease.




Slide it into the bore. Set it in good.





Your piston will go in on top of that. Don't forget to grease that too.

 

Now here’s the fun part…. Best case scenario, You should use a tool like this to set your cir clip.


Unfortunately, I only had one of those $2 Multi tipped, Harbor Freight specials. Not only is it bad quality… Neither the straight nor the 90 degree tip will reach all the way into the bore necessary to set that clip. That is unless you modify! I had to grind down the straight tip back to the set pins to get more reachable length. Even then it was a while of muscling the clip into place to the point of ALMOST giving up and thinking about ordering the right tool for the job. Then… it happened… Snap! I couldn’t believe it. It went in! The next MC i rebuild will include the tool with the new parts in the order.



Now sneak your dust boot on. Len’s full rebuild kit also comes with new screws for the top as well as the diaphragm for beneath your cover.





Fast forward to the carb clinic and install… Let’s remember why we’re here… The old rusty, crusty MC that believe it or not was still in service. The PO actually did put on stainless steel lines but the connections were getting rusty, they were not coated and they were definitely not the correct length.




And yes, that SAE bolt was going through the MC to hold the cover on.



So… Out with the old…



And in with the new… Including Len”s stainless steel braided brake lines.






Remember those rebuilt calipers from the beginning of the thread? Here’s one…



More Assembly… Before…



Getting there…




Beautiful fit…

 

Then of course, once you put it all together, you have to fill and bleed the system. I feel like I’ve read 1001 horror stores about this taking days. Truth be told, once everything was assembled and fluid was put in, Saftie and I as well as some of the others spent a fair amount of time taking turns pumping the handle, holding, releasing at the bleeder valve, etc… Here and there a small bubble would emerge but at that pace, it was clearly going to take weeks to get a firm brake handle.

Then...

In steps Dave…

He began doing something that I like to refer to as “The Hogfiddle Jiggle.” Ever so small agitations of the lever (like tiny, tiny squeezes). Man you had to see the bubbles rise from the weep hole in the bottom of the MC. I’m not joking, it took less than 5 minutes to get a firm lever. Amazing.


Job done now. My new brakes did the carb clinic group ride as well as the run north in Lake George that weekend. Since home, no hiccups what so ever other than an annoying squeak which I’m hoping will dissipate at some point.


Much thanks to everyone who helped out including Saftie and The Crazy Gnat and of course Dave once again for his care and know-how and hosting the annual CNYCC each year.

 

Excellent!

 

Awesome write-up, Nuch!

 

You have earned a sticky.

 

Glad you liked it!

Thank you!

 

Awesome pictures. It was like I was there .

 

It really was (and always is... 3 years running so far for me) a great time. I'm already looking forward to next year. Having a bunch of XJ'rs together for a day is really great. I make a "Me Weekend" out of it. Too bad it's only once a year!

 

I realize the last post on this thread is almost a year old. But I just picked up, about two months ago, an '86 Maxim X and will be rebuilding the calipers and MC this winter. My question relates to the spring plates that help hold the pads in place: I just put new pads in my bike and did not pay attention to the positioning of those brass colored plates. Does it matter which way they are installed as they seem to function the same either way? Thanks in advance for the advice

 

Yes, they seem to have a longer tab/shorter tab thing going on in there... Either way is ok...

 

Perfect and thank you for the quick response! I used to sell bikes many moons ago and had an '85 Maxim X that I bought new. Unfortunately, I sold it and the rest is history, lol. I look forward to restoring the X I have now and appreciate immensely the wealth of info on this forum. Your post about the rebuild is phenomenal and will assist me this winter Have a great day!!

 

The parts fiche diagram should be helpful.

front-brake-caliper

 

Thank you! It's hard to tell for me from the parts fiche pics. My 55 year old eyes, lol

 

If you mouse over the picture you can zoom in as close as you'd like.

 

Got it, thanks again!

 

Thanks Nuch. Great write-up. I'll add a photo for people like me who were stumped at getting the plastic cover off the back of the caliper - push the sides together and there are two tabs on either side that will release.

 

Regarding bolting the caliper halves together (do they bottom out, is there a torque spec, etc.)

So on that note... I think the shop manual suggests 22 ft-lb for a generic 14mm bolt (10 mm thread). I will tell you that 40-45 ft-lb is where one of my bolts started to strip... I had that sinking feeling where it's suddenly getting easier to turn vs. requiring increasing force. Arrgh.

 

Oh No! The fluid transfer seals helped me to determine how much torque to apply. Once I couldn't see them anymore between the halves, I went "really good and tight" and stopped there.

 

That is the worst feeling ever. You feel like it's just about there and it starts to feel lighter!

 

I am going to start the rebuild of my front caliper. This post looks very helpful. Where would I get the rebuild kit from?

I rescued a XJ700 Maxim X from my neighbors yard…it was running when he parked the bike around 20 years ago…still turns over!!!

RobertM

 

Many years after this post.....Sure helped me.....THANK YOU !!!