My brake refurb thread (XJ750)

Ok, so I'm deep into the refurbishment of my brake system. I got the screw out that I had to drill the head off of, got the MC off as well as the calipers.

First issue, MC: That damn retaining clip. I bought some clip removers, but they aren't long enough to get into it. I'll have to find another pair that's longer and thinner. After that, I don't think I'll have too much problems refurbing the MC.

Second issue, calipers: Those damn pad retaining bolts won't budge at all. I'm worried I'm going to strip it out. I also noticed that both dust boots for the sliding pins on one caliper are missing. It's wonderful to find out all of the issues from the previous owners!

Now, don't get me wrong, it sucks fixing issues from the past, as well as spending a lot more money than you anticipated, but the brakes and the tires are really the only issues right now, and I have two new tires on the way. However, the only long ride I took was awesome. I love the power and torque of the bike, and I can't wait to get everything sorted out. Thanks for the help so far guys. I'll keep you posted on the progress.

 

Since you're rebuilding the calipers it won't hurt anything to soak them overnight in a 50/50 mix of ATF and Acetone to help free up the retaining pins.

 

k-moe, could the acetone in that mix attack the paint? that paint is tough but so is acetone

 

It could, but my calipers could do with being repainted; I'm assuming that his could too.

 

Ok, the rebuild has been on hold while I waited for parts and tried to attack the calipers. A buddy of mine from work invited me to his house, since he as a bunch more tools than I do.

First things first, getting the pad retaining pin out. We used a regular hex key and made it a two person job, one to twist and one to hold the caliper and surprisingly, both came out fairly easily. Getting those pistons out, though was the hard part. One piston was stuck; one pad had almost no wear while the other pad was nearly all the way down. We tried the air gun trick, and after spraying some penetrating oil around the piston, they both finally popped out. First, though we used a c-clamp to push the pistons back into the caliper to free them up a bit.

My buddy also had a small pair of needle nose pliers that was able to get that retaining clip in the MC out. My snap ring pliers are still on their way, and seem unnecessary! I'll get around to rebuilding everything next week, as I'm still waiting on some more parts. I bought some new pads from e-bay that have arrived, but while disassembling one of the calipers I realized it was missing both dust boots on the slider pins. So, another $40+ to xj4ever, and they should arrive next week.

Now to invest in a vacuum brake bleeder!

Thanks for the tips guys. I'm slowly but surely getting there with the front brakes. Once that's out of the way, I'll get both tires and the back shoes (have everything already) put on. I bought some Bridgestone S11 Spitfire RWL tires for her. I think they'll look awesome with my blacked out bike (no emblems except on the motor).

 

You'll want the snap ring pliers when you go to put the snap ring back in. Getting them out of a recessed bore is relatively easy. Getting them back in without the correct tool, not so much.

You can skip the vacuum bleeder. Invest in a large syringe from a farm store and some appropriately sized vinyl tubing. Reverse bleed from the caliper up. That will give you the best chance of getting all the air bubbles out the first time.

 

Hey guys, i was searching threads on caliber re-builds, seen something about useing air to push out the pistons. Did'nt find acual thread but figured i knew what the idea was, and it worked great except only one came out first and now not sure how to get the other one out ? The one still in is not frozen, it started moving with the air, but now can't hold pressure with one out. any help out there

 

I used a piece of rubber to block off one side and bolted the two sides together and used the air to push out the side that was not blocked off. Then reversed it and got the other one out. I also put some rubber between the piston and the other side of the caliper to prevent any damage if the piston came out too fast.

 

I agree that this is a great way to bleed the brakes. After completely rebuilding the m/c, both calipers, and installing stainless steel brake lines it took me about 15 minutes to completely bleed the brakes.

 

Thanks tabaka, was wanting to get them out so back out to the garage and kinda figured it out. i used smoth cardboard from back of a writing tablet and bolted back together and it did work. too late about the flying piston, they do come out in a hurry when they come,( same bitch my wife has ) sorry bout that one, i could'nt resist ?

 

So I cleaned up the MC and put the new parts in. It was pretty easy once I had that snap ring tool. Hooked it back up and installed the brake lines. I'm still working on the calipers. I rebuilt them today, but the pistons in both calipers went in just a little ways, then tightened up. Are the pistons supposed to be in the caliper super tight? I DID lube up the seals and the outside of the piston when I put them back in. One tool I still need to buy is a c-clamp.

 

BUy the C-Clamp. The seals....seal, which makes the brake piston difficult to put in just by hand.

 

Got the C-clamp, got the piston pushed in and the pads installed. That pin fits in there tight! Now I just need to buy a 6mm hex wrench that I forgot when I was at the parts store to thread the pin in... I do have a small syringe for doing a reverse bleed of the brakes, so it might take a little bit to bleed them, but I'm shooting to have the front brakes done this weekend.

 

Alright, got the calipers on and everything hooked up. I tried to do what k-moe suggested and reverse bled the brakes. I got fluid in the MC, then added fluid through the other caliper, but there is still a ton of air in the system. The pads were a bit off of the rotors, but pumping the brake and then doing some more bleeding, they are now touching the rotors, and I can see them start to bite when I pull the handle. It's still super spongy, but getting firmer. It's just taking forever to bleed. I'm taking a break (haha!) tonight and I'll finish bleeding tomorrow. In the meantime, I have the handle tied down and I'll let it sit overnight. Thanks for all of the help so far.

On an unrelated note, I stopped by the local Yamaha dealer and asked if they had any JIS screwdrivers, then I told them that I had a Maxim. The lady told me to get rid of it since they don't make parts for it anymore, it has 4 cabs I'll have to sync, blah blah blah! Lame. I've looked EVERYWHERE in town for a JIS screwdriver, and everybody just looked at me like I'm from another planet or something...

 

I got my JIS screwdrivers from Len, they are my favorite screwdrivers now!

 

Wow, the tie-it-down-overnight method works great. After an hour and a half of pumping and bleeding last night, I JUST started to get a little pressure on the handle. So, I took some big twist ties and tied down the handle overnight, and like everybody says, viola! The pressure is towards the bottom of the handle travel, but walking it in my garage (it's raining today) I am able to stop instantaneously, which is much better than it was. Once the weather breaks I'll cruise around for 1 or 2 hundred miles and then re-bleed.

 

If there is any air left in the system you can take a vibratory sander and work your way up from the calipers to the master cylinder to get it all out (hint; there is still air in the lines, BTDT).

 

How should I do that, k-moe? With MC lid on or off, and with brake handle pressed or depressed?

 

Tie the brake handle to the grip, lid can be on or off.

 

I'd say that my front brake refub is complete. I didn't get a chance to hit it with my sander, but I tied the handle down again this morning before work. When I got back 11 hours later, the handle was as hard as I was when I was watching olympic beach volleyball. There was a wrist injury the first day of that event, but don't worry, I'll be fine in a couple of days.

On a serious note, I took it for a nice long ride this evening and the brakes feel great. I'm still going to take it easy on them for a bit to bed them up. Now I need to put some air in the front forks and make an appointment to get my tires replaced and rear shoes installed. I should be good to go after that!

 

Solo rider the forks only need 5 to 7 PSI. No more than 20 (the manual says 32 psi max, but I feel that's too high even with new fork seals).

 

My Haynes manual says 5-17 psi. I can only find one air valve and it looks like it's connected to both forks. Does the 82 xj750 only have one air valve for the forks?

 

The Maxim only has one air valve With a crossover hose; the Seca has separate valves on each fork leg.
The service manual goes into more detail than the owners manual. 17 psi is for two-up riding with gear, but all values are guidelines. The max PSI is 32, but as I said it's not recommended to run that high.

 

The 82 750 Maxim has the crossover hose. The 83 750 maxim is separate.

~Ghost

 

On an unrelated note, I stopped by the local Yamaha dealer and asked if they had any JIS screwdrivers, then I told them that I had a Maxim. The lady told me to get rid of it since they don't make parts for it anymore, it has 4 cabs I'll have to sync, blah blah blah! Lame. I've looked EVERYWHERE in town for a JIS screwdriver, and everybody just looked at me like I'm from another planet or something...[/QUOTE]

I bought this set of Vessel JIS screwdrivers. Didn't realize Chacal had them. In any case, this is a great set and I keep them safe and secure.

http://www.vesseltools.com/hand-too...cle-restoration-repair/view-all-products.html

 

It's not uncommon anymore for dealers to not know what parts are available. Too many have fallen into the hands of people who are not passionate about motorcycles, and are willing to hire people who aren't pasionalte either. I was amazed the first time I went to a dealership and spoke with a parts guy who didn't even ride! That used to never happen. You'd see nearly every employee at a local track on Sunday.

 

I'm not quite sure it's that they're not passionate about motorcycles (although your parts guy is a tool, no pun intended!), I just think they're more passionate about money than dealing with our 'old crap'. The lady at the parts counter at my local Yamaha dealer straight up told me to get rid of the Maxim, probably hoping that I'll want to buy a new bike from them. Yes, I know these old bikes need some love and attention, but it really is a great bike, a nice combo of cruiser and standard. I'm not a fan of cruisers, and I hate the v-twin sound. Nothing sounds better to me than an old-school inline 4. Well, maybe that sick inline 6 on the Honda CBX. Still some things to address and wrench on, but I just got back from a ride and I'm still feeling awesome I fixed the brakes myself, and wrenching a bit is why I got an older bike.