DIY Tundra Brakes (BBK)

[bloc]

I have a high quality 9/16 drill bit at home and a pretty poor quality 14mm step bit.. but still no time to go to the local LKQ to try and modify a knuckle. I hope to knock that out this spring… sorry it won’t help with your bad caliper.

I do think drilling the knuckle will be fairly easy with a good bit, going slow. But don’t know for sure yet.

 

[CharlieS]

I haven't tried this specific job, but in general, I find that sharp high quality drills make a huge difference (in addition to appropriate speeds and lots of cooling/lubricaton). I've had good luck with Precision brand HSS (high speed steel), working well, but not breaking the bank. I love my drill doctor for keeping drills sharp.

 

[bloc]

I haven't tried this specific job, but in general, I find that sharp high quality drills make a huge difference (in addition to appropriate speeds and lots of cooling/lubricaton). I've had good luck with Precision brand HSS (high speed steel), working well, but not breaking the bank. I love my drill doctor for keeping drills sharp.

Sharp seems good, until you are only cutting 1mm per side. That’s when it can almost be counterproductive, by letting the bit grab and bind. I suspect this is what @supercarrera was dealing with.

I’ve done work like this in a welding shop but not with the kind of metal I suspect the knuckle is made of. Which is exactly why I want to do a dry run on a knuckle that doesn’t matter before getting into mine. If it goes well I’ll be ordering parts and putting this together pretty quick. The parts have gone up about $50 since we posted about it earlier..

 

[lx200inAR]

I’m more apprehensive about the brake line retention issue than I am about drilling the knuckle, for whatever reason. If there was an easy and obvious solution for that I might feel differently but since I can’t machine aluminum I don’t know if I trust myself with adhesive and zip ties to do it correctly on something as critical as brakes.

What's to worry about? Just make sure you've got your wild kingdom jammies on and go to town.

But seriously, dealing with aluminum isn't difficult. You can use word-working tools to cut it, and it's very easy to drill. (i'm not advocating either method, as they both have their merits). Just saying aluminum is easy to work with.

 

[bemerritt]

I’m more apprehensive about the brake line retention issue than I am about drilling the knuckle, for whatever reason. If there was an easy and obvious solution for that I might feel differently but since I can’t machine aluminum I don’t know if I trust myself with adhesive and zip ties to do it correctly on something as critical as brakes.

I have the ability to do better than zip ties, but I feel absolutely fine with it

 

[TeCKis300]

For enlarging the hole in the knuckle, I wonder if a drill with an impact function might help it work better with more cutting torque and lower speed to minimize heat?

 

[doru]

The issue with enlarging a hole that is part of a safety car feature is how to ensure the hole keeps the same axle after enlargement. For enlarging holes the right tool is a reamer not a drill. Drills require a drill press of some sort or a very skilled eye & hand (which many do not have). Reamers are self centering in the existing hole. Here is an example of how reamers look like Amazon product ASIN B000OV9HSGYou'll have to find one that is the right size for your application. You still need some skill but not as high.

 

[bloc]

The issue with enlarging a hole that is part of a safety car feature is how to ensure the hole keeps the same axle after enlargement. For enlarging holes the right tool is a reamer not a drill. Drills require a drill press of some sort or a very skilled eye & hand (which many do not have). Reamers are self centering in the existing hole. Here is an example of how reamers look like Amazon product ASIN B000OV9HSGYou'll have to find one that is the right size for your application. You still need some skill but not as high.

@supercarerra tried a reamer for enlarging the hole and couldn’t make it work. It did work well to clean up the hole after the other bits were run in though.

I tried to find a stepped drill bit of the correct size but that is a specialty part for machinists and extremely expensive.

 

[TeCKis300]

The issue with enlarging a hole that is part of a safety car feature is how to ensure the hole keeps the same axle after enlargement. For enlarging holes the right tool is a reamer not a drill. Drills require a drill press of some sort or a very skilled eye & hand (which many do not have). Reamers are self centering in the existing hole. Here is an example of how reamers look like Amazon product ASIN B000OV9HSGYou'll have to find one that is the right size for your application. You still need some skill but not as high.

I agree that a reamer should be the right tool. I suspect part of the challenge is that we're asking for it to remove more material, of a tougher type, than reamers are designed for.

A stepped bit has advantages here but the problem is that it can't cut deep enough.

I haven't done this, but as a strategy, this may have a better (and cheaper) chance at working:

1) Start the enlargement with a stepped bit to the target 9/16" size
2) Use a 9/16" cobalt drill bit to follow through

Centering of the 9/16" bit should be much improved with the hole the stepped bit started.

High torque, moderate to high pressure, low speed, and use cutting oil.

 

[bryson]

What's to worry about? Just make sure you've got your wild kingdom jammies on and go to town.

But seriously, dealing with aluminum isn't difficult. You can use word-working tools to cut it, and it's very easy to drill. (i'm not advocating either method, as they both have their merits). Just saying aluminum is easy to work with.

Not sure which aluminum components you're cutting, but the caliper and knuckle are both steel... Or are you just talking about making a small bracket to retain the brake line? Either way, those are some rad jammies!

 

[lx200inAR]

Not sure which aluminum components you're cutting, but the caliper and knuckle are both steel... Or are you just talking about making a small bracket to retain the brake line? Either way, those are some rad jammies!

I was referring to making the aluminum bracket rather than drilling out the steel knuckles.

 

[bloc]

Got to the yard to play a little bit. Couldn't find a later model tundra with the 12.2mm through hole but I did find some toyota knuckles.. the internal threads will do a better job of centering this cheap-ish 14mm step bit, but it at least cuts the metal without issue. I have the stuff on the way to bolt on 16+ brakes and before long will pull one of my calipers and rotor and attempt using this tool from the back side just to see how well it stays centered. My thought is if it is a problem as long as I don't take out much metal I can toss the stock bolt back in and regroup.

I also tried a sharp 9/16 bit, as well as a reamer.. for the latter, absolutely terrible. Too much metal to cut, I'm guessing. It tended to start wobbling in the hole, and with the number of flutes was barely cutting anything at all. On the sharp bit, things were going well with a fair amount of speed and light pressure, then it grabbed and twisted.. which chipped the edges of the cutting faces. With a method to provide even pressure and stabilize things I think a sharp bit could work, but free-hand with a drill it will be a problem.

I didn't get a bunch of pictures but this seems the most promising method. I'll update and start a dedicated thread as I get this put together. This will still need to be enlarged to 9/16 aka 14.2-4 mm and at this point I believe the reamer will be a problem for even this cut. I have spent a bunch of time looking and can't find a straight 9/16" step bit. If someone knows how to find one.. please post.

 

[bloc]

Edit: sizing is wrong. I'll dig some more for appropriate one.

Thoughts? 9/16" ball-end carbide tipped bit. 1/2" shank to fit a normal drill, though being such hard steel they may have trouble gripping it. I could grind flats into it I guess..


Amazon product ASIN B000P4JSFE

 

[TeCKis300]

Got to the yard to play a little bit. Couldn't find a later model tundra with the 12.2mm through hole but I did find some toyota knuckles.. the internal threads will do a better job of centering this cheap-ish 14mm step bit, but it at least cuts the metal without issue. I have the stuff on the way to bolt on 16+ brakes and before long will pull one of my calipers and rotor and attempt using this tool from the back side just to see how well it stays centered. My thought is if it is a problem as long as I don't take out much metal I can toss the stock bolt back in and regroup.

I also tried a sharp 9/16 bit, as well as a reamer.. for the latter, absolutely terrible. Too much metal to cut, I'm guessing. It tended to start wobbling in the hole, and with the number of flutes was barely cutting anything at all. On the sharp bit, things were going well with a fair amount of speed and light pressure, then it grabbed and twisted.. which chipped the edges of the cutting faces. With a method to provide even pressure and stabilize things I think a sharp bit could work, but free-hand with a drill it will be a problem.

I didn't get a bunch of pictures but this seems the most promising method. I'll update and start a dedicated thread as I get this put together. This will still need to be enlarged to 9/16 aka 14.2-4 mm and at this point I believe the reamer will be a problem for even this cut. I have spent a bunch of time looking and can't find a straight 9/16" step bit. If someone knows how to find one.. please post.

View attachment 2956782

Nice test.

So that I understand, you started with the stepped bit to get as far as the 9/16" rung would get you? Then tried following through with a 9/16" standard drill bit, and it still grabbed and chipped?

Thinking out loud, with the standard bit, maybe follow-in with light pressure and high speed? To maximize centering and reduce the chance of grabbing? Hoping heat will be minimal as it's cutting less material in this use than a full bore hole? High speed is risky to wrists however, but maybe bracing the drill handle against a leg or something else to minimize that risk?

Carbide ball-end could be interesting!?

 

[CharlieS]

Is there enough carbon steel flat surface that you could attach a mag drill to it? That might hold the drill steady enough so it doesn't twist. You could probably rent one.

Also, if not already, maybe try a 135 degree drill. I was told that they cut hardened steel better.

 

[CharlieS]

Would a 1/2" annular cutter work? Honestly, I just learned about them, but they seem like they could be great for this.

 

[bloc]

I used the 14mm total diameter step bit as far as I could before the body of the drill started hitting the hub flange and I couldn’t go any further. At issue was on this vehicle the steering was locked so I couldn’t turn the knuckle and attack it from the CV side.. that would allow full depth of cut. But again the internal threads may act as a guide to help center this bit. I’m not sure if our 12.2mm smooth hole will have too much slop to stabilize the 12mm step of the step bit effectively.. that’s why the next step is try it from the back side of my knuckle.

I believe mag is out based on the surface just not being flat or broad enough, though building a jig that bolts to the other caliper bolt hole is an idea. Or even the hub face if there is more clearance between the outer diameter and bolt hole for the drill body.. the 4runner knuckle I was messing with didn’t clear but ours might. I’ll look at that on my truck soon.

Annular cutter is a great idea.. hadn’t heard of those. Thing is I think the 1mm per side step is a lot smaller than most of those are designed for.

On the carbide ball-end bit I’m hoping the existing hole is enough of a guide to keep it straight through. They are cheap enough I may order one of those and go to the junk yard again.

 

[Bryanmc]

@bloc I’m thankful for your effort working on this. I’d be happy to cover any costs for test bits you’d like to try out. I’m watching you patiently.

 

[bloc]

Forgot to say.. I then went in with the 9/16” drill and tried to go further than the 14mm step could reach. This is where cutting seemed to be working, but it eventually caught and twisted the drill. This is a regular cordless drill so not a huge heavy duty gear train to tweak a wrist or anything.. but it did somewhat booger up the hole and as mentioned chip the cutting edges of the bit slightly.

@Bryanmc I appreciate it.. I found what looks like the perfect tool with a 12mm shank and a 14mm step, made out of carbide, but it is a specialty machining bit and hideously expensive. We will figure this out though. Sounds like about five people took advantage of the current sale to stock up on 2016 brake parts, so it’s safe to say there is movement in the direction of making this more common.

 

[grinchy]

How hard is it to pull the whole knuckle? Then just take to a machine shop and have them do it, or jig up in a drill press and do it at home.