Tips for Removing Brake Caliper Bolts; Fitting Damper pads

[blaster56]

Thinking of replacing brake disks & pads on my 2007 Boxster S. Any suggestions on best way to approach removal of the brake caliper bolts to minimise risk of shearing the bolts ? Car is not garaged so I’m slightly worried about the bolts being difficult to shift.

Also, what are brake damper pads and how are they fitted ? Haven’t seen much detail on this point.

Any guidance much appreciated.

 

[kasspa]

Simple enough DIY, bolts on my 996 4S torqued to 63lb & despite what is suggested they do not need replacing every time..... damping pads are secured to back of pads via strong adhesive & fit into caliper pistons.....

In my experience the biggest problem was releasing the pad retaining pins as they were covered with brake dust + corrosion & were difficult to knock through without rubbing down with some emery cloth..... or similar....

hth

Paul

 

[blaster56]

Thanks Paul.
Any merit in using a release spray on the bolts before attempting to remove ? I saw a comment elsewhere suggesting the bolt threads should be cleaned up on the way out but not sure how to do that if they’re still in the hole !

Andrew

 

[Motorhead]

Steel and aluminium aren't great partners Andrew..! Maybe some penetrating oil would help ease the threads?

As Paul says, I'm sure that it's not essential to replace the bolts. Just make sure that the all the bolt and caliper threads are clean before reassembly.

Here's a useful video describing how to replace the pads - https://www.youtube.com/watch?v=vsLZFxO5c2M

Jeff

 

[MrDemon]

What am I missing here, ? No need to remove the calipers !

 

[kasspa]

Just answering the question by OP but agreed no need if just for pad replacement....
Well spotted []

 

[vitesse]

OP does state he wants to replace discs & pads.Can be a good idea to use impact sockets with side fit to minimise any risk of damaging bolt heads but I've never needed to.
Frequently had to use a sliding rigid bar initially with a Manchester spanner to "crack " the bolt then a long swivel bar followed by ratchet`.GT85(or similar) sprayed into the ends of the tapped holes where you can see the end of the bolt thread helps & a little Loctite threadlok is a good idea when re-using the original bolts,
Porsche advice is seemingly based on aircraft/turbine technology where the bolts are intended to be stretched but providing they are properly torqued up using a torque wrench,normal road use & even PCGB track day use is never likely to cause slackened caliper bolts in my opinion.

 

[blaster56]

Would a Manchester spanner be closely related to a Birmingham screwdriver by any chance ?

 

[vitesse]

Quite possibly but makes a different sound on impact[]

 

[chrishak]

It's your braking system we're talking about here - the caliper bolts are stretch bolts and aren't expensive so why on earth would you not follow Porsche's recommendation and replace them? IIRC the new bolts are Torx headed which superceded the original Allen headed bolt (on my 986). There's a good chance you'll need a new 'R' clip or two, so I'd buy a fitting kit which includes the retaining pins but IS a bit pricey for what you get (and won't necessarily need).
I was concerned about the bolts shearing but a bit of gentle pursuasion with a long breaker bar and all was well.

 

[vitesse]

You can't stretch a bolt unless there there is a clear hole around it with a nut against a surface at the opposite end-in a caliper fixing you can only apply excess torque ie. a shearing force by overtightening.
I agree there is a possible amount of locking effect because of the clear hole in the caliper as you torque up to the quoted figure partly because of the friction of the head against the caliper surface,but the rest of the bolt thread is still free to rotate .
As a precaution & possible H&S regulations it is recommended by manufacturers -

 

[Motorhead]

I agree Colin. Tightening a steel bolt in an aluminium (?) caliper there's only one material that's going to stretch first..!

Manchester spanner? I'm not familiar with the term but many years ago when working in Italy the technicians referred to an adjustable spanner as a chiave Inglese (English spanner) - because it adjusts to every situation..!

Jeff

 

[vitesse]

Jeff-a Manchester spanner normally refers to a heavy ballpein hammer sometimes with it's associate -a large lead mallet commonly carried by machine fitters usually accompanied by as you say a quality adjustable wrench.(very rare for them to speak Italian in Manchester)

 

[blaster56]

Many thanks for your help, all. Will be replacing the bolts. Fitting kit might well be worthwhile too.

one last question. Do you know if the rear damper pads are also self adhesive ? Videos suggest the front are.

Andrew

 

[vitesse]

And of course that is why course threads of generally a slightly larger diameter than necessary are used when fastening into aluminium,even higher grades.

To a millwright,a course thread is one that needs a considerable degree of swearing as well as a Manchester spanner.[]