drilling rotors
 

ok i bought the marlin brake combo #1 for my 81, i just got everything today except the master cylinder cause apparenty they're on backorder for 2-3 weeks, didn't say anything before i ordered it... anyways now i have some free time andi want to drill my rotors, anyone know the best way to do this or have done it before? any help would be nice, thanks in advance

Drilling rotors yourself without professional equipment is generally not recommended.

If the edges of the holes aren't properly tapered/smoothened, they will eat away at your brake pads very fast. Also, if you don't space the holes too close you will end up cracking your rotor between holes, or if you space them too far you get no benefits.

That's why on front-heavy vehicles it is usually better to buy slotted rotors because it eliminates the danger of rotor failure without reducing the benefits.

:facepalm: Why would you want to mess with the most critical part of your truck?

cause i just wanted to reduce brake fade and i had the spare time. i havn't decided if im doing it i was more testing the idea

Bad idea.

:wabbit2:

From what I have been told by manufacture engineers is that drilling rotors actually is worse for rotors due to the drilling takes away from the vacuum action in the vents of the rotors. Cross drilled rotors are actually useless unless you have air ducting supplying direct airflow over the rotors, for everyday drivers you want slotted rotors.

:good:

well if i had a rotor i would slot them but i don't. and why's it a bad idea if you correctly do it?

You gain nothing but holes in your rotor at best, busted rotors at worst.

Drilling a hole in your head would be more useful :hillbill:

:wabbit2:

look at a crawl mag... now look at the racing buggies, they all have drilled rotors, they look like frickin swiss cheese, they do it for a reason. idk if im going to try it myself but there obviously is a benifit

Look at the weight of their buggies, Rockwells, 1 ton axles, 44+ inch tires with 500+ HP...you got a 22R that turns our 90 squirrels on a good day.

Vented rotors w/ V6 calipers up front and vented rotors with rear Toyota discs and my 85 stopped 39.5s with ease on or off road.

Drilling rotors on a Toyota rockcrawler is pointless IMO.

:wabbit2:

best thing on a wheeler is a blank rotor.


cross drilling is for weight reduction ONLY. This is why you normally only see them on drag racers.
Side effects: weakens the rotor, more prone to warping when hot + less surface area for the pads to bite on, therefore less braking power.

Slotting is to minimize any glazing on the surface of the pad when they get hot.
Side effects: Less surface area for the pads to bite on, therefore less braking power + gives mud and dirt to collect on the rotor when off-roading, therefore less braking power.

Don't want your rotors to glaze over from heat? Get better pads. Ones that are not organic based that heat up and gas out and were designed for hotter temps. Keep in mind most brake pads also have a tolerable heat range. It is possible to use too hot or too cold of a pad.

You only see a benefit from CD/SL rotors at high speeds. This is why Ferrari etc etc use them, but their rotors are huge and increase the surface area back to where a smaller blank rotor would be. Ferrari rotors are also forged units which reduces the possibility of the rotors cracking and warping. Most aftermarket drilled rotors are just that, drilled.

You won't see a true Auto Crosser use CD/SL rotors either. Most good drivers all use good pads and blanks.

and how big are these rotors? And how fast are they going? See above comments by me. :D

alright, the only reason i thought about the fade is i've gotten it bad before with factory brakes, going down mountain roads around 50 mph and also in the sands. but good to here waskilly for your brakes cause that's exactly what im going to run but on 35's.

my v6 front brakes stopped an 87 4runner (SAS) with 35x15.5" SX's on 15x10" steel rims (about 120lbs per rim+tire) downhill with relative ease, no fade

The stock 81 brakes were designed for a 225/75/15. Big brake up grade was the best thing I have done to my truck
Edit - still piecing the parts for my reAr disc, another good mod is to throw an IFS rear end on your truck, reAr drums are 2" bigger. That will help a bit too

Ya im putting in the ifs rear just running disks though