Master cyliner screws 1 - Kroil 0

Squirted some Kroil on to the front brake cylinder screws last night.
Tried to remove the screws this morning.
No go.
The heads are stripped so I tried the Sears screw remover tips.

The front brake works fine so I am in no hurry. I do have good screws from the parts bike to use as replacements.

I could conceivably just swap the cylinders.

Any opinions?

 

Interesting you couldn't get them off with the screw removers. I used a nail set on mine. Make a dimple on the edge of head the angle the set and drive the screw to loosen head.

Someone shared that trick a while a go and it has worked well for me.

 

I ended up using the Craftsman screw extractor and it worked. Did you break the extractor, or just make a bigger hole in the screw?

 

+1 with Bill on the nail set. I had one of those buggers that wouldn't come loose for nothing, soak many days in rust eater. Stripped the head, only thing that worked was the nail set & hammer it into submission.

 

Fitz, the screw heads are almost complete "holed out". Not much left of the original phillips slots.

I have a nail set that I can try. Can't hurt.

Thanks guys.

 

Another method that is similar to the nail set and/or cold chisel is to use a spring loaded centre punch (SLCP) around the edge of the screw in the direction of removal. I has a stuck carb hat screw and when I used the SLCP you could actually see rust flying off. Might be worth a try.

 

No joy. Tried the center punch and it just pushes the slots metal around.
I have sprayed Kroil on the screw more than a couple of times.

It looks like switching master cylinders with the parts bike is on the horizon.

 

Just drill-out the screws and re-tap the two holes at the next metric oversize.

You'll have to run the drill through the two holes on the cover too.

 

If you CAREFULLY drill away at the heads with increasing-size bits you should be able to eventually drill the tapered head off the screw and lift the cover off leaving two ragged stubs that might more willingly be extracted with vice-grips and heat.

I can't believe the Craftsman screw extractor didn't work. Are you using the double-ended type? I used mine on two MC screws (one on each bike) on the big phillips that holds the clutch cable bracket on, and on one sidestand switch screw and it worked every time. I used my cordless drill so I could go slow but still have plenty of torque.

 

Fitz, I have used an impact wrench on the phillips screws on the cover plates and have 100% success so far. No such luck on the master cylinder screws.

Rick, what size tap and screw do I need to get to do the drill and tap and replace?

Thanks guys......

 

I don't remember exactly what size that new hole got tapped out to.
I'll have to pull-out on of those Cap Screws and measure the threads.
I should be able to get that done by this evening, sometime.

 

I've had luck here with left handed drill bits, a bit larger than the screw diameter. As they cut through the back side of the head they tend to grab and run the screw out. When not, the head comes off and they are usually easy to unscrew then.

 

MiCarl

The Sears EzOut is a left handed drill bit for all intents and purposes. The screw metal is so soft that the EzOut just chews up the head slots.

Rick,

Thanks. I will try to get the tap and screws once I know what to get. All of my taps are English. I don't own any metric taps, yet.

 

Hey any excuse to buy tools I think you 'll find them required. I didn't own any taps until I started fixing up mine. I have used them on several occasions already.

 

Try a set of vise grips, I tried and tried on mine but i could not get them loose or open without distroying the body. what did I do? Bought a brand new one off of ebay for 40 dollars no regrets here.

good luck

 

+1 on an excuse to buy tools!

Seriously, a cheap metric tap and die set is almost a necessity for working on one of these things, even if the PO wasn't some sort of Neanderthal. (Carb sync: "so easy a caveman could do it" er...at least TRY anyway)
I was blessed with a fastener-swapping PO, so I've put mine to great use already too.

 

Will do, fellas. I will get the metric taps and some new screws.

Getting the front brake cylinder and fork seals up to snuff are on my list for pre-spring tuneup.

 

I have one of the screws off of the parts bike master cylinder.
What are the threads of this screw. M4.5 ?
If so, then M5 is the next over-size?

 

Oh, and yeah Fitz, carb synch is almost brainless with the bottles. I may make a set and send them to you so you can try them out.

 

Looked up Harbor Freight on their web site. $25 gets a nice metric set of taps and dies. I'm headed there in an hour or so.

 

Cant figure out what the thread pitch is for the master cylinder screws. The screw does not seem to go easily into any of the metric dies that I bought today.

ARGH!!!!!

 

Half my taps have a thread gauge - I pulled one of my MC lid screws - looks like an M4 x .70

 

Bill, that did it. Thanks.
The screws were so rusty that they did not go through the die easily.
So, I cranked the screws and the rust came our of the threads.
Now I have a couple of screws to try after I drill and tap the holes.

Cheers..........

 

Cool. If you got them both out you should be able to just clean the threads with you new tap.

 

I used a "Single-hole" Pliers-type Paper Punch to enlarge the hole on the Rubber Gasket.

Don't try to drill it!

DAMHIKT : )

 

my service manual for my xs400j 1982 says my master cylinder screws are as follows . I can't think of a reason as to why they would change the specs but here it goes .

M5x0.8 tightened @ 6.5 foot pounds

 

I find this Thread particularly interesting. Chiefly because, ... a) I don't own an Inch Pound Torque Wrench ... and, ... b) because even if I did have the best one that money could buy; I probably wouldn't use it.

No offense, ... but, 6 to 7 Pounds means: "Tighten it."

After doing the tightening of generic fasteners foe awhile; I believe to develop a feel for how tight a NON CRITICAL fastener needs to be.

Covers on Master Cylinder, Headlight Screws, Fasteners holding-on clamps, Muffer clamps and stuff like that ... I just tighten. If I fear that it might come loose; I add a smear of LockTite.

Critical Torque, I respect and do right.
I have a Sears Torque Sensing Wrench I spent a half-hour engraving ON and OFF near the Ratchet Lever to have a Visual reference that prevents me from hearing clicks instead of applying torque.

I have always lived by the advice, given to me as a boy, when I Torqued a Manifold Stud to the right load on an MBG and stripped the threads.
I had no problem getting the thing out. But the guy who owned the garage told me fixing it doesn't get charged to the customer. That was my mistake.

So I'd rather tighten-up a fasten a dozen times ...
Than break the fastener once.

 

Speaking for myself I have never developed the skill necessary to tighten multiple fasteners on the same assembly to the same "tightness". For example, the front cover on my baby wing has 5mm bolts around the perimeter. I would not consider this to be a critical assembly. It just basically supports the clutch activation lever, the oil filter/cover and holds the oil in. If the seal fails it would likely seep oil. A pain in the.a** but nobody dies. If you tighten those little bolts down to the proper torque level, up to 43.2 in lbs I can't feature how you could break it off. IMHO the key is to tighten the fasteners to the correct and more importantly a uniform amount.

Some of us have the touch and some of us probably don't. Those of us who lack the skill and experience must rely on whatever crutch is available to get us by. Considering that the majority of the fittings are small diameter threading into aluminum I have to depend on my choice of crutches the in/lb torque wrench.

 

Thanks for posting on this thread. I have enjoyed reading the responses.

Update - The master cylinder screws are absolutely frozen.
I drilled them both out to 1/16". Used the threaded extractor and broke off one screw head. The other screw now has a broken-off extractor tip in it.

I will now swap the master cylinder from the parts bike. The screws on that master cylinder cover go in and out easily.

The mirror mount has mirror remnants frozen in place. More frozen fastener fun before I can do the swap.

 

I sure don't blame you.

 

i use my old sears cordless drill with the clutch settings behind the chuck for noncritical covers
start at 1 and go around once then move up to 4 or so go around again
after you do it once you get the feel for it, then go over them by hand to
tweak them
your wrist is very accurate if you only need the last 1/4 turn, and can do them quickly

 

Interesting "thread" guys .... what you are "feeling" is the elasticity of the bolt material as it tensions up. At first the assembly is "snug", ie. the gasket has compressed and the parts are basically together but the bolt has not begun to stretch.

As you apply torque to the bolt head the only thing that can give is the shank of the bolt. As the bolt begins to stretch you can feel this elasticity in the wrench. If more and more torque is applied the bolt will eventually fail in combined torsion and tension, if the thread in the mating part is not stripped first.

Where problems often arise on bikes is that we have a habit of replacing screws with stainless or high tensile steels which have a much higher "modulus of elasticity" than the material into which they are being screwed, ie. the aluminium will yield way sooner than the fastener. In this case you don't get anything like the feedback to the wrench of the fastener yielding if it were screwing into a material of similar strength. In most cases the fastener is not being loaded to anything like its design capacity.

Every seasoned mechanic develops a "feel" for correct bolt tension however most will still use a torque wrench on critical assemblies to control gasket compression and thereby assembled dimesions. If in doubt, measure it and apply common sense. Don't be like the guy who insisted the correct tension was easy to determine in every situation:

"Keep tightening until you break the bolt then back it off half a turn!!"

 

This whole issue wasn't caused by overtightening; this was a case of some very complete and thorough corrosion.

 

I agree, Fitz. It appears the brake fluid was not changed regularly and the screws were rusted completely frozen. The parts bike master cylinder screws came out easily.

 

Heh, I love this thread. The only time I had to drill out master cylinder screws they didn't some out until the backout bit went all the way through the screw and into the cylinder. Luckily it didn't go through the bottom of the MC.

How's the remains of the mirror in your new cylinder coming?

 

I tried to take off the mirror remains and it did not budge.
I sprayed it with Kroil and am letting it sit for a day or two and then I will go at it with Vice Grips.

 

I'm having exactly the same problem with one of the screws on my front master cylinder assembly (mounted on right front handlebar). Both flush screw heads were almost completely stripped, however, after some careful work with the Philips head screwdriver, I was able to remove one of them. The other appears to be totally frozen in place. Tried using WD-40 as a 'pre-treatment', but that doesn't seem to have helped. Next, I tried using a stripped thread screw extractor (purchased from Home Depot). After drilling the specified 1/8th inch deep into the stripped head, I applied the 'remover' but it still didn't do the trick. I hesitate to persist, since the possibility of breaking off the screw shank in its death-grip is a very good one (as with 'Half Century's' experience). The recalcitrant screw is thoroughly and completely frozen (undoubtedly due to corrosion, as previously mentioned). As an alternative, I've been searching the internet for a replacement (used 'donor' unit) cylinder assembly, but they (at least a specifically XJ900RK unit) appear to be very hard to find. One question I have in that regard is this: will a used front master cylinder assembly from an XJ650 or 750 work as a replacement? Or are they different enough to make this approach impracticable?

I note that YouTube has several useful videos dealing with stripped screw removal, one of them involving an ordinary broad rubber band (used to provide extra traction for a stripped-screw extractor), and another that recommends using a small cold chisel to whack the screw head laterally, so as to loosen it a bit, but this screw I am dealing with seems impervious to everything. I am contemplating attaching a small thermonuclear device to the screw head, but I'm afraid the collateral damage might be rather severe...

Am I truly 'screwed'?...or does someone else have some further first aid recovery technique to suggest? Thanks.

 

I am wondering if it would move with a few taps with a light hammer on an inpact screwdriver assuming you can get a grip on it. Or can you cut a slot for a straight screwdriver in the screw head with a dremmel without cutting into the top cover of the master cylinder?

 

Kalikiano I sent you a PM...

 

First of all, sincere thanks for the responses & suggestions. Somewhat encouraged, I went out to the bike this PM with a good friend who has a strong grip and we tried the screw-extractor one last time. This time, we sank the drilled-out hole a bit deeper into the screw head and he put some extra down-force on the extractor, while canting the approach angle a bit off by a hair. This apparently enabled the extractor head to bite significantly further into the screw head and...VOILA!...out came the stubborn screw.

An examination of the troublesome screw revealed some corrosion around the beveled head of the screw and NOT around the shaft of the screw itself (as I had expected). A bit of a surprise, I guess, but it just shows that anything is possible when it comes to a component giving one difficulties. I guess the main lessons here are 1) two heads (and hands) are better than one, 2) don't admit defeat too soon in the battle, and 3) replace the flush-headed screws with a slightly protruding-headed screw It still looks fine, but gives a bit of extra surface for emergency removal, should such extra measures be needed.

All's now well in XJ900RK-land! Cheers, all!

 

Both excellent ideas, Franz, that may well help in future scenarios dealing with this sort of problem. My problem was (as remarked earlier) fortunately solved late this PM through the use of a friend's extra 'torquey' grip and a reapplication of that screw extractor I mentioned. Sometimes it takes two to deal with a poser like this, I've found. I do have a Dremmel tool, as well as an impact driver (but lack a small enough Philips bit to do the job, regrettably) and had contemplated trying to use it, but the screws are maddeningly situated just inside and below the right-side lip of the handlebar-attached windscreen, making it necessary to remove the screen before getting a straight vertical shot on the screw-heads (with clearance enough for the impact driver). I was about to do just that (not really enjoying the extra complications involved) when w finally were able to get the screw out. All's well that ends well, I guess!

My Kawa ZX-900R Ninja (named 'Fugu', since like the liver of the Puffer Fish, it can kill you stone cold dead in exactly 2.65 seconds!) is a much newer bike (2000), with its 'modern' screw-on cap master cylinder brake reservoirs. The older Yammy bikes with their XJ style reservoirs do tend to be problematic with occasional 'frozen screw' problems such as I had. I seem to recall I had exactly the same screw problem with my 1982 XJ750, some years back (wish I still had that bike...I loved it!).

 

We have all been there with a stuck component and another try fixes it. Fugi is fast but it's the other road users we have to watch too especially the mobile phone users. Good you got the bike sorted. All the best.

 

remember to put some anti size on those screws the nickle type not the copper type. service your fluid every year as you should to remove water from fluid.
Chacal sells allen head screws for the mc. thats what I replace the oem screws.