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Posted by: cassmcentee Mar 27 2020, 02:00 PM

Is the rear rotor held on to the hub by these two screws at this point?
I have Soaked/Heated/Hammered but the screws aren't budging.
Am I missing something here???
My guess is they are rusted in place...
I have a torch with a rosebud tip, didn't heat the rotor to red thinking that I could possibly warp the rotor...so I just went close to red...
Do I have to drill these and then tap them out?

Thank You,
Cass

Posted by: porschetub Mar 27 2020, 02:19 PM

Put a punch which is about the same size as the recessed hole and hit very hard with a hammer,then use an impact wrench the fits the slot properly,if this fails center punch (dead centre) the screws and drill them till the heads are gone.
Once the disk is off the remains of the screws should wind out with ease,good luck.

Posted by: mepstein Mar 27 2020, 02:25 PM

MAP torch is your friend.

Posted by: kroelofsen Mar 27 2020, 02:45 PM

Drill them out...

Posted by: Bmw635 Mar 27 2020, 02:47 PM

Could try this impact driver. Hammer the handle and the bit will twist in direction you want while pushing the tip in to prevent rounding.

Posted by: cassmcentee Mar 27 2020, 03:05 PM

Okay, Great!
So they are the criminals holding tight then.
I have hammered and given a couple of attacks with my impact
Will soak tonight, heat/hammer/impact in the morning again...
Drill out if all else fails.
Thank ya'll

Posted by: jsaum Mar 27 2020, 07:00 PM

I’ve had good luck using PB blaster. Let it soak for a few days then use heat. MAP gas gets hotter than standard propane, I’ve heated then spayed to cycle from hot to cool. Get the metal expanding and contracting to break the rust loose.

Posted by: GaroldShaffer Mar 27 2020, 07:24 PM

Drill the heads off then pull the rotor off. Once that is off use a vise grip to clamp on the remaining threaded stud and slowly twist out. You still may need to heat it, but you won't hurt the hub. I agree with using a MAP torch to heat with.

Posted by: 914forme Mar 27 2020, 07:33 PM

And if the rotor is stuck, big puller will work, put two lug bolts, so the rotor and puller don't go shooting across the garage.

Posted by: IronHillRestorations Mar 27 2020, 07:41 PM

I'd probably keep soaking it with Seafoam Deep Creep or 1 part ATF with 1 part acetone, those are the best penetrating fluids I've found. I'd also take a screwdriver and hammer and tap straight in on the screws, like you're driving it in, several times a day. It might take a couple days but the fluid will work it's way in. If you don't want to wait then take Garold's advice and drill off the heads of the screws.

The rotors have two threaded holes for screwing an M6 bolt in to pop them off the hub.

Posted by: 914forme Mar 27 2020, 07:46 PM

Thanks Perry, learned something new today.

Posted by: mepstein Mar 27 2020, 08:00 PM

The guys at the shop use a MAP torch because they want to get it done in minutes instead of waiting days for penetrating fluid. It's a very useful tool for working on old cars.
The trick one of the guys taught me is to touch the cooling metal with a piece of paraffin. The wax will wick into the threads and make it easier to loosen while penetrating fluid will just evaporate.

Posted by: Amphicar770 Mar 27 2020, 08:14 PM

Try one of these
https://youtu.be/Pwz-NXj5ZIk

Google aircraft screw extractor and you will find similar.

Posted by: Spoke Mar 27 2020, 08:20 PM

I had the same problem with my 914. I drilled the heads off but the rotors were rusted to the hubs. Had to pound the rotors off with a hammer. I was replacing the rotors so didn't matter if they were beat up.

Posted by: bkrantz Mar 27 2020, 08:38 PM

This is my favorite and always successful tool, that I keep around just for that job.

Posted by: 914werke Mar 27 2020, 09:34 PM

Motorcyclists are probably very familiar
Ive wore out a couple of these

Posted by: bdstone914 Mar 27 2020, 10:12 PM

@http://www.914world.com/bbs2/index.php?showuser=22304

After you get the screws out you may find the rotor stuck to the hub. There are two threaded holes that take an 8mm bolt. Screw in two bolts sequentially tightening. Most all rotors that fit over hubs have them.


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Posted by: Porschef Mar 28 2020, 06:07 AM

Last time I used this was for exactly the same purpose. Clean the slot thoroughly, make sure the tip fits properly. Heat, spray in some PB Blaster, Liquid Wrench, or penetrant of your choice, (yes, the ATF/acetone works well, been using it for years, but you need to shake frequently to keep it mixed), repeat, seat the impact square and whack it but good with a lumpy hammer.

It’ll come off, and provide you with a sense of accomplishment...

Posted by: cassmcentee Mar 28 2020, 07:53 AM

Thanks Ya'll!
I wondered what those other two holes were for
Makes perfect sense

P.S. I've been using my acetylene torch with a rosebud tip.
Had to heat the axle nut to RED just to get it off.
This car sat on the ground for way too many years.

Posted by: Jamie Mar 28 2020, 09:09 AM

[quote name='Bmw635' date='Mar 27 2020, 12:47 PM' post='2798273']
Could try this impact driver. Hammer the handle and the bit will twist in direction you want while pushing the tip in to prevent rounding.
[/quote

Don't overlook the fact that these impact drivers have Forward and Reverse settings.

Posted by: 76-914 Mar 28 2020, 09:36 AM

[quote name='Jamie' date='Mar 28 2020, 08:09 AM' post='2798529']
[quote name='Bmw635' date='Mar 27 2020, 12:47 PM' post='2798273']
Could try this impact driver. Hammer the handle and the bit will twist in direction you want while pushing the tip in to prevent rounding.
[/quote

Don't overlook the fact that these impact drivers have Forward and Reverse settings.
[/quote]
I just use the tips from the impact hammer anymore. I use them in my air impact and it works great. Just keep a lot of pressure against the screw head and keep it square. I tried to remove some large Philips head screws from a Karmann Ghia door hinge using the impact tool and did nothing more than scar a few. Got pissed off and put the bit in my 1/2" air impact wrench and Bingo they all backed out. Even the few I scarred.

Posted by: Jett Mar 28 2020, 09:49 AM

Use a torch, works every time

Posted by: cary Mar 29 2020, 12:36 AM

What Kent said ............. Impact driver bit holder slips right on your 1/2 impact
gun. Hold it tight or you'll break off the bit. One little blip is usually enough.

Posted by: cassmcentee Mar 29 2020, 11:11 AM

Heated the surrounding area to Red
Hit the screw with a 6mm socket
With calm pressure used a Makita impact gun with the proper bit
Screws came right out without scars!
Easy Peasy!

Didn't have any 8mm bolts handy
Used gentle hammering on the rotor till she budged a wee bit
sprayed the exposed gap with PB
Some more gentle taps and Whalla! Off they came

Thank you for the help!
Sincerely,
Cass

Posted by: Solocholo Sep 9 2021, 09:16 AM

Ya my bolt that holds the rotor on is stuck too? Broke two 1/2 drives, and a 4 foot breaker Pipie, now the rotor is stuck too, this car has been sitting 30 years,