Front Brake Job non-brembo

[Session101]

So I am going to do a front brake job on the bike, number one, the bike stops fine, it just squeals when im lightly stopping on the front brake. also the brake light only comes on when i squeeze the hell out of the lever.

So here's the plan, I will replace the pads, was just thinking of shopping on ebay, any recommendations? i was just going to go EBC pads...

2nd do i really have to resurface the disc? i know i should but do i really have to? i don't think i could afford a new disc and how can i tell if it needs to be replaced?

and lastly i was going to try the reverse brake bleeding, Im sure once i do this it will clear out the lines and maybe the the brake light sensor would be more "sensitive" when i just squeeze the brake lever rather than have to mash it down to get a response.

hoping this is a less than $90 job

[Mike V]

Session,

Without knowing the condition of your rotor; just a few thoughts and recommendations.  I expect some others to lend some helpful thoughts.

Resurfacing or turning our rotors isn't a suggested process.  Unless you are experiencing severe pulsing through the hand lever I'll assume your rotor is in decent condition and may only need a deglazing.  Any deep radial score marks in the rotor?  I would use a wet-dry ±220 grit paper and carefully deglaze the rotor.  A glaze buildup on both your pads and rotors is probably what's causing your squeel. if you have the rotor(s) off the bike, support it on a protected flat surface.  If not, do the deglaze with the rotor on the wheel carefully not to stress the rotor in a lateral direction. They will warp if mistreated and unsupported.

My next suggestion might seem like a belt & suspenders approach but in my opinion - a good idea if fitting new brake pads.  And that is to clean the holes on the rotor with a gun bore brush fitted into an electric drill.  These holes can collect a lot of debris that can contaminate new pads.  There's a buch of them - get comfortable. After the hole cleaning use a non-residue solvent to clean the rotor.  I use acitone or isopropyl alcohol on a clean shop rag or cloth.

My personal preference is OEM pads - you can select whatever type fits your budget and preference.

Be sure to flush the entire system with fresh clean brake fluid. I suspect your brake light is coming on possibly by a low fluid level or faulty electrical connection.

After assembly, please don't forget to burnish or break-in the new pads.  This is too often overlooked and is a very important procedure for your new brakes to operate well.  Find a safe secluded roadway, accelerate to ±30mph and brake hard to a full stop.  Continue 10 to 20 times being sure to allow the brakes to cool during the procedure.  Don't allow the brakes to overheat, after a few stops run the bike through the gears to get some air flow across them and cool down.  Then continue with the burnishing procedure.  Some pad manufacturers specify this process, you may ask who is supplying them to you for specifics.

I have no experience on reverse bleeding.  I bleed my brakes conventionally with Speed Bleeders.  Regardless of what procedure you use - be sure to remove all the air out of the system.

Good luck.  Happy Braking.

-Mike V.

[Session101]

should i just wax-on wax-off sand by hand or can i use my palm sander on the disc?

also i watched a video on brake bleeding, its half reverse and half the regular way but i will need another body:

It seemed they pushed fluid from the bottom in the reservoir and then sucked up what came out till it was semi-clear, then just started dumping brake fluid in the reservoir and then leaving the valve open started pumping till it was clear on the bottom end. Seemed legit

[disco51]

I'd start first with pulling the brake pads and checking the thickness.  This should give you an idea whether the pads are a problem and need replacing.  
Bleeding the brake fluid is a must do annual event.  Really not that hard.  I've never tried the method you describe, so can't comment on reverse brake bleeding.  The conventional method works fine and just requires a clear hose connected to the bleed screw and a small bottle that the tube runs into it (ie pretty cheap).  Flush until the brake fluid is clear and no air bubbles.  Just remember to keep filling up the reservoir.
Snowbum has an entire section on brake squealing in his brake article.  I'd recommend reading this as it might provide some insight.  Your pads and rotors may not be the problem.
Good luck.

[Barry]

I use the bottom up brake fluid fill using a large syringe and it works very well but it's only really appropriate when the system is full of air after a complete overhaul.  

For the routine fluid change I'm not sure how efficient bottom up fill would be at displacing all the old fluid, Would it mix on the way up ? And you would have to remove it from the reservoir which seems messy.  I use the normal top down bleeding method which allows the old fluid to be collected at the bottom.  

On the brake squeal, I'm with Mike V on not aggressively removing material from the disc as there is precious little wear allowance to start with. I would just deglaze by hand and clean with aerosol brake cleaner.

The squeal may well come back anyway if it's caused by the caliper pistons not retracting the pads sufficiently. Short of a caliper overhaul, exercising the pistons can help and you will be doing that anyway to fit new pads.

[Mike V]

Guys,

Let's discuss this brake squeal issue while it's "resurfaced" again.  Seems to be a common problem and often a sought after resolve.  I'll share my personal opinion on this issue.  Seems like a lot of folks like to apply the brake squeal goop to the back of the pads to get rid of squeal.  Personally; I feel this is treating the affect and not the cause of the squeal problem.  Squeal is caused by trapped gasses and glazing (hardening) on the pads and rotors.  At least that's my belief.  Prolonged light braking is often a cause of glazing = squeal. When I notice my brakes starting to squeal I simply perform several (safe) hard braking maneuvers as previously described at a secure roadway and the noise diminishes. The thought of applying goop to the back of my pads has always made me a little uncomfortable.  Seems to me if it was necessary for our brake system the BMW Gods would have included this material as OEM product. Work as it may for a while - it seems to my way of thinking only treats the problem and does not cure it.

Penny for your thoughts...

-Mike V. / San Diego

[steve hawkins]

I would also carefully inspect the disc for cracks radiating outward from the holes mentioned above.  Any cracks will make the brakes squeel

If you only have one rotor and it is heavy grooved or has cracks, you should replace it.  Someone will chime in with other options, but I have a single full floating disc.  I have replaced my hose/s with the stainless steel braided variety and the fluid is changed regularly.  You got to make the best of what you have.

Cheers

Rev. Light

[Bob_Roller]

Do you still have the OEM rubber brake line(s) ?

If you do , replace them .

I have a thread going on in Chit Chat about my oilhead brake failure .

Got all of the lines replaced yesterday with braided stainless replacements, what a difference !!!!!

The squeal you hear, is the pads vibrating on the caliper .

There is a spray product by Permatex called 'disc bake quiet', it's a plastic material that keeps the pad in contact with the piston, kinda 'glues' them together, but they come apart easily .

Remove the pads and see how worn they are, they may just need a bit of sanding to remove any glazing that may be there .

The minimum thickness for the rotors, is .180 in., I think that's around 4.5 mm .

Don't have the rotors machined, my '84 LS had the rotors machined by the previous owner, to remove the heavy grooves that normally occur with OEM rotors .

I found 14 cracks between both rotors, the rotors had been machined to about .140 in thick .

The EBC graphite pads are great with EBC steel rotors, I don't know how they are with stainless OEM rotors .

I use a vacuum bleeder, makes quick work of the job .

[montmil]

A few hard stops has always quieted down my front brakes... as long as the pads are within specs. Turning the brake rotor usually results in a too thin for safe operation rotor. It takes awhile, but new pads will conform to the rotor "grooves" as you follow the pad break-in procedure.

As to the brake light issue, have you examined the brake lever-operated switch? Confirmed it is correctly installed.  

[Bob_Roller]

I think the '80 model year bikes may still have the pressure switch under the tank, not on the mechanical switch on the  handlebar control , but I'm not sure .

If you have the pressure switch arrangement, it may be telling you that the brake system pressure is not where it should be .

[Mike V]

The squeal you hear, is the pads vibrating on the caliper .

Thanks for adding the key word I left out of my post in regards to glazing, Bob.  

Glazing of pads/rotor = vibration = squeal.

-Mike V.

[montmil]

If you do have the pressure activated switch, a proper brake bleed after pad replacement will probably sort out that issue.

Highly recommend bleeding the lines "top down". Speed Bleeders... I love 'em.

[Luca]

What about the condition of the anti rattle springs?  I just got a new set for my ATE calipers, as they had both popped their rivets and were a bit worse for wear otherwise.  I got one mean squeal going on (but they're probably glazed too... wet braking is dangerously woeful

[Bob_Roller]

I bought my '81 R65 in January, '81, from the day I got it, the wet braking was in my opinion, 'dangerous', to the point that I refused to ride it in wet conditions .

In May, '07, I replaced the OEM rotors with EBC semi-floating steel rotors and EBC graphite pads .

I will not hesitate to ride in the worst deluge that happens to occur since the brake parts replacement, it's made that much of a difference .

Just one persons opinion here .

[Barry]

I think the '80 model year bikes may still have the pressure switch under the tank, not on the mechanical switch on the handlebar control , but I'm not sure .

Pressure switch is on the brake pipe union behind the head lamp shell.