Brake Disc Screws Rusted 987.1 2.7L

[magycks]

As per the title the 2 little screws are rusted on all 4 corners and I can't get them out with a screwdriver (it just strips the heads)

What's the best way to get these out, especially as they're so small? I've seen these screw extractor kits so would appreciate any advice!

[magycks]

Slippydiff said:

If you haven’t got an impact driver :

https://www.amazon.co.uk/Silverline-427633-Impact-...

and don’t want to purchase one, use this bush fix :

Use a nice sharp centre punch close (ish) to the outer radius, make a light punch mark, then angle the centre punch in this mark pointing in the direction you want to undo the screw, and hit it hard.
They normally slacken after the first couple of blows, but if not, keep going until the punch hole breaks into the crosshead slot, then do the same on the opposite side of the screw.

I don't have an impact driver but I have a DeWalt hammer drill and impact wrench (both 18v) so i suppose I could buy one... just never had a use for one before. How would an impact driver help when the head of the screws are stripped / will strip before the screw turns?

RobXjcoupe said:

If stripped and rusted, just drill the head off the screw

I could do this, but then i'd be left with the rest of the screw inside the threaded hole. I want to be able to use new screws

[magycks]

I’ve already replaced brake pads on all 4 corners. I bought the discs to do them at the same time but came up against these screws

I’ve seen these screw extractor kits; are they a good buy / do they actually work on rusted cars as this is very different to a stripped screw around the house?

[magycks]

tozerman said:

Agreed, as other have said. You need an impact driver and a big hammer. That's it..
No need to piss about drilling etc..

How does a manual impact driver with a big hammer compare to an 18V battery impact wrench like the Dewalt DCF887N? Only interested in ability to remove rusted screws

[magycks]

Slippydiff said:

I fear you’re of the opinion your impact gun may be a substitute for an impact driver. It’s doubtful it will. The two of them work in differing ways, despite both using impact.

By all means try using your impact gun, if you can keep the bit located in the screwhead, you may be successful, but if you’re not, you’re going to round the heads off and then be back to square one and then having to utilise the methods that have already been suggested.

I don’t want to appear belligerent, but you do seem hellbent on NOT listening to what I and others are suggesting/telling you is the best way forward

No no, sorry think there's a bit of confusion. To clarify:

I currently have a DeWalt Impact Wrench (DCF899N) which is not appropriate for this job and I fully accept that. Apologies if i've miscommunicated on this point.

People have suggested purchasing an impact driver which I shall most definitely do. There are manual impact drivers (like the Silverline one you very kindly recommended Slippydiff) which are used with a hammer but I'm also aware there are battery powered impact drivers like the DeWalt DCF887N (which would use the same battery as my existing impact wrench but performs a different function).

My question is what is the best tool for the job i.e. the hammer (~£10) and manual impact driver (~£10) vs an 18V electric impact driver (~£95 + battery i already have)? I'm happy to spend the money on whichever is best (or even get both)

Hope that makes sense. I've not disregarded anything that's been said but trying to ask questions where my knowledge and experience is lacking. Really appreciate all the help!

RobXjcoupe said:

When the head is removed it removes the tension on the screw. Remove the disc spray the screw studs in releasing oil, let soak for a couple of hours then use a pair of mole grips clamped tightly to the stud and unscrew.

Thanks for the tip on releasing oil; I have ordered some WD40 Fast Release Penetrant

[magycks]

steveo3002 said:

get the hammer one ...prefer a better brand than silverline

if that fails drill the heads off

Thanks. Any brand/product recommendations?

[magycks]

I've just ordered the silverline impact driver (~£10) and a 2.5lb OX Club hammer (~£10) off Amazon so hopefully does the trick. Thanks for the help all

Would still be interested in view around the electric impact drivers; i'm guessing there's less control so easier to strip the heads of screws?

[magycks]

Slippydiff said:

The De Walt info states " Precision Drive mode offers additional control in screw driving applications to avoid material and fastener damage", I'm just not convinced it's the right tool for the job, that's not to say it won't do it, but it's not THE tool for the job, whereas the "manual" Draper/Silverline hit it with a hammer is, from my perspective, but I was rattling spanners for a living 40 years ago

Given the choice. my old fashioned method (taught to me the then apprentice, by a time served often-pissed Irishman nicknamed Paddy, who was an excellent mechanic (not fitter) and did the job right) using a centerpunch and a hammer would always be my first plan of attack. As I've said, it's NEVER failed me, and all too often the disc retaining screws are either seized or have previously damaged heads, or both ....

For the record, I don't have an impact driver of any description, and I've replaced my fair share of corroded Porsche and BMW brake discs over the years, read into that what you will !!

Many thanks Slippydiff - your responses have gone above and beyond. I'll heed your advice and see how we go!

[magycks]

Given my disc brake screws could use replacing, anyone know what size & spec they are / where to buy some replacements? Better than putting the mangled ones that will come out back in!

[magycks]

thebraketester said:

Didn’t your new rotors come with replacement screws, most do.

I don't think they did, no

[magycks]

Ended up having to drill the screws out. No amount of rust penetrator, smashing an impact driver, hammer etc for 30min would get them moving.

Good news is I replaced the front 2 discs

The bad news is that my friend and I snapped a brake line (i think?)!! Can't believe it! Fluid all over the floor...

I think this is the part I need to replace (just to make absolutely sure i'm ordering the right thing). Imagine it will be a struggle due to the rust

https://www.design911.co.uk/fu/prod137872/Caliper-...

Edited by magycks on Tuesday 16th June 23:32

[magycks]

I bought the new brake line and fitted it without any issues. The old bolts were quite rusted but got them off with rust penetrant and hex sockets (I cut the old metal line with pliers to get a socket on to minimise any risk of rounding the bolts). Did some light impact wrenching on the higher bolt and overall an absolute breeze versus what I was expecting.

I kept bleeding the brakes on all 4 corners and kept the reservoir topped up with DOT 4... for a lonnggg time but I've now realised that because the reservoir had run so dry I need to use a computer to activate the valves (as the vehicle has traction control). No wonder our brake bleeding efforts weren't getting us anywhere! Does anyone know if I can get a ECU reader that can do this inexpensively / does anyone have one I could borrow near south-west London?

"For cars with traction control or Porsche Stability Management (PSM), you need to use the Porsche System Tester 2 (PST2) in order to activate the valves in the hydraulic unit during the bleeding process."

[magycks]

Klippie said:

Over the years having to replace disc's I've found the retaining screws are made from chocolate and very easy to drill out with normal HSS drill bits and a squirt of cutting fluid, the screws serve no pursose apart from keeping the disc on the hub there is no load on them, there is no requirement to make them from hardened steel.

Draw a file across a new one and you'll see how soft they are.

I had to drill out the screws on the front but the rear disc screws came out easy with a few bangs of my new impact driver. The retaining screws are certainly useful but by no means required

[magycks]

Mike1960 said:

Hi, you should be able to bleed the brakes without activating the ABS unit. The valves will have held the fluid in the unit.
The 986 brakes and clutch share the same fluid reservoir and if this has run dry then you may need to also bleed the clutch. This is a b*****d of a job. Have a look on YouTube and take your time.

was bleeding all 4 corners in the correct order repeatedly but sadly didn't work. No improvement at all.. guessing because the brake fluid had a whole week to drain out and probably need the software..?

[magycks]

Mike1960 said:

How much fluid did you bleed through. The entire system is about 1.5ltr.
Have you used more than that?

Bled through over 1 litre of fluid but no air was coming through for the last 45mins we were doing it.

DH986S said:

Have you bled both sides of the calliper that you replaced the brake line on, I had a similar issue when I replaced these lines.

Yes, we bled all 4 corners and both sides of each calliper in the correct order. We did this for a very long time but it doesn't work. We've bled brakes many times before on other cars without any issues hence the confusion until we googled and found out we needed the computer to put the car in bleed mode.

If anyone has a computer that will put a 987 in bleed mode or could recommend a low cost tool that will do it, that would be really helpful.

[magycks]

RobXjcoupe said:

Just wondering, what happens if you turn the ignition on, then bleed the brakes? So in effect the abs unit is actually active but obviously not being driven

We tried this as well but to no avail. We spent a crazy amount of time brake bleeding and only once we gave up did we realise we need the software to do it properly

I don’t know if some kind of crazy traction control activating driving could make any difference - not that I would want to try when the brakes struggle on a 5mph to 0 stop as it is!

Think we just need to get a hold of the computer by the sound of it... unless there’s some other way

[magycks]

mickyh7 said:

I refer you to my past post!

Haha. Well I did manage all the discs and pads plus brake lines without any issue. Everyone provided lots of helpful advice which I really appreciated

Bleeding the brakes would have be no issue at all but hadn’t been aware of the need for software, so that’s the next hurdle.

I’ve got other cars and I like to learn to do things myself so it’s no biggy

[magycks]

Hi all, I've moved the brake bleeding question to a new thread as it's quite different from the original post:

https://www.pistonheads.com/gassing/topic.asp?h=0&...