Open Road

Well, I'm back with another adventure. I'm hoping to get advice and suggestions on my Rear brake hose and caliper refresh.

I unfortunately jumped into this thinking that I could be like Dwayne and do this based on his procedure without a full understanding of what it really takes to do it.
https://rennlist.com/forums/928-forum/4 ... -pics.html

Now I'm stuck.

My plan was to replace the rear hoses (with SS hoses), Paint/refurbish the calipers(with kit)/shields and replace the rotors and pads with new. I've had my 928 for 15+ yrs and never had to replace the brake pads etc in that time. They've always passed inspection and still have a lot of meat on the pads. The rotors are still in good shape too. But, I want new.

My first mistake was trying to disconnect the Left side hose from the hard line with a Combination Wrench (like Dwayne) instead of a Line Wrench and rounded the nut. I then bought a Line Wrench set. But, too late. Nut is too rounded.

I tried PB Blaster and even ATF/Acetone mixture before hand, to no avail. I cut the rubber line so that I can at least remove the caliper, rotor and shield on the Left side only. (I have not touched the Right side at all yet)

The rotor took a least a hour and half of banging and wedging/shaking to finally release. What an ordeal! Before I attempt the Right side, what can I do to disconnect remaining hose from the Hard line without further damage to the hard line connection? Or am I fucked?

This is before the 11mm nut was rounded.


Can the mounting bracket be removed from the body to get better access or is it welded in place? I removed the holding clip also. But that can be reinstalled, if necessary.

I assume that this is similar to what the end of my hard line looks like correct? (image stolen from a thread by Seth)

Rick, you need heat. Extreme but carefully-targeted heat.

https://boltbusterinc.com/

Some folks have apparently gotten good results with Chinesium Harbor-freight quality induction heaters.

A ‘hand torch’ is disrecommended; it will melt other stuff before the union nut gets hot enough.

Beg, borrow, buy, or steal an induction heater and then report back for safety and process tips.

to make it easier to remove the disc, you need to unwind the handbrake shoe adjuster, large cog.
there is a hole in the disc to get at it with a screwdriver and fully unwind it
cheers
Phil

worf wrote: ↑Mon Mar 10, 2025 3:01 pm Rick, you need heat. Extreme but carefully-targeted heat.

https://boltbusterinc.com/

Some folks have apparently gotten good results with Chinesium Harbor-freight quality induction heaters.

A ‘hand torch’ is disrecommended; it will melt other stuff before the union nut gets hot enough.

Beg, borrow, buy, or steal an induction heater and then report back for safety and process tips.

Dave, I will look into getting one. I'll report back. Thanks!

h2pmr wrote: ↑Mon Mar 10, 2025 3:36 pm to make it easier to remove the disc, you need to unwind the handbrake shoe adjuster, large cog.
there is a hole in the disc to get at it with a screwdriver and fully unwind it
cheers
Phil

I realized after that I did have the E-brake still on. I bet it would have helped to have it off. Thanks

The e-brake procedure is in the WSM, btw. And has pictures.

Hi Rick,

I changed the soft lines on my car last year and had the same problem (rounded nut).
I also damaged the rear steel hard line at the same time...
I followed Dave's advice (thanks again Dave) and bought an induction heater. It did the job.
The rear left one was the worse.
No way I would have been able to remove that one without heat and line wrenches.

I also removed the muffler (from cat) to have a better access. And if I remember well, because of that I had access to that bracket nut and removed it to have a better access.

Here's the link of my thread here on this:
Rear Brake line Seized - Fixed
A lot of good information there.
And yes, you need to have the hand brake off to remove the disk. Don't ask me how I know. :)

Bertrand Daoust wrote: ↑Tue Mar 11, 2025 9:01 am Here's the link of my thread here on this:
Rear Brake line Seized - Fixed
A lot of good information there.

Ah hah! I thought I was experiencing Threadjà vu (the feeling you’ve seen this thread before.)

My highschool autoshop teacher would slap you on the back of the head if he saw you touch a line with anything but a line wrench.

Heating a connection helps, but a good added trick is to cool the inner part with penetrant.
It will be pulled into the space between the parts.

Bertrand Daoust wrote: ↑Tue Mar 11, 2025 9:01 am Hi Rick,

I changed the soft lines on my car last year and had the same problem (rounded nut).
I also damaged the rear steel hard line at the same time...
I followed Dave's advice (thanks again Dave) and bought an induction heater. It did the job.
The rear left one was the worse.
No way I would have been able to remove that one without heat and line wrenches.

I also removed the muffler (from cat) to have a better access. And if I remember well, because of that I had access to that bracket nut and removed it to have a better access.

Here's the link of my thread here on this:
Rear Brake line Seized - Fixed
A lot of good information there.
And yes, you need to have the hand brake off to remove the disk. Don't ask me how I know. :)

Thank you brother! I will check out that thread.

On a positive note. Otto has agreed to send me his induction heater. What a great friend. When I receive it, I will post for Dave's instructions.

N_Jay wrote: ↑Tue Mar 11, 2025 12:52 pm My highschool autoshop teacher would slap you on the back of the head if he saw you touch a line with anything but a line wrench.

Heating a connection helps, but a good added trick is to cool the inner part with penetrant.
It will be pulled into the space between the parts.

Yes, I needed that slap first before I started this project. I did not understand the softness of that nut/connection!

Also, I plan on painting my calipers. My neighbor who is a car guy (not a Porsche guy) suggested POR-15. He's used it on his calipers before. He said you clean up what you have and just paint it on with a stiff brush and it self levels to a hard finish.

https://www.amazon.com/POR-15-45008-Glo ... r=8-7&th=1

Has anyone tried this? I know it's good for rust prevention. But, would be good for the calipers? The shields I'm painting Silver. Calipers to be Gloss Black.

WyattsRide wrote: ↑Tue Mar 11, 2025 2:12 pm When I receive it, I will post for Dave's instructions.

Read that thread first; my suggestion are in it. And post any questions there. That way we’ll have one thread for this procedure.

You should also order the replacement hard line for that branch. With the union nut rounded out, the OE piece ain’t gonna be useful.

WyattsRide wrote: ↑Tue Mar 11, 2025 2:45 pm Also, I plan on painting my calipers. My neighbor who is a car guy (not a Porsche guy) suggested POR-15. He's used it on his calipers before. He said you clean up what you have and just paint it on with a stiff brush and it self levels to a hard finish.

POR-15 ain’t what it used to be. OR, IOW, 10-ish years ago it was great. Now, it’s so thin and watered down you have to do 2 to 4 coats and it’s nothing but brush-stroke-looking when you’re done.

Look to one of the bespoke caliper paint systems.

Also, don’t just paint them. Restore them completely: new piston seals. Replace rusty hardware etc.

Kinda thing calipers deserve every 40 years or so.

worf wrote: ↑Tue Mar 11, 2025 2:47 pm

WyattsRide wrote: ↑Tue Mar 11, 2025 2:12 pm When I receive it, I will post for Dave's instructions.

Read that thread first; my suggestion are in it. And post any questions there. That way we’ll have one thread for this procedure.

You should also order the replacement hard line for that branch. With the union nut rounded out, the OE piece ain’t gonna be useful.

Crap! OK on the new hard line and questions on Bertrand's thread.

worf wrote: ↑Tue Mar 11, 2025 2:51 pm

WyattsRide wrote: ↑Tue Mar 11, 2025 2:45 pm Also, I plan on painting my calipers. My neighbor who is a car guy (not a Porsche guy) suggested POR-15. He's used it on his calipers before. He said you clean up what you have and just paint it on with a stiff brush and it self levels to a hard finish.

POR-15 ain’t what it used to be. OR, IOW, 10-ish years ago it was great. Now, it’s so thin and watered down you have to do 2 to 4 coats and it’s nothing but brush-stroke-looking when you’re done.

Look to one of the bespoke caliper paint systems.

Also, don’t just paint them. Restore them completely: new piston seals. Replace rusty hardware etc.

Kinda thing calipers deserve every 40 years or so.

I plan on restoring with kit from Roger.

WyattsRide wrote: ↑Tue Mar 11, 2025 3:29 pm I plan on restoring with kit from Roger.

Cool.

This thread can be focused on the caliper restoration.

Disassembled, cleaned and painted the calipers and shields this weekend. I didn't acid bath or have them sand blasted. Just cleaned and wire brushed them the best I could. I'm not the greatest or most patient painter. But, I think they turned out pretty good.
Here's what I used. Black for the calipers and other little parts and silver for the shields.


Some before and afters.

I didn't take a picture of the shields after the paint and clear coats. They turned out great. (I'll add the painted soon)

After cleaning


Calipers (Disassembled based on Dwayne's write up)

After painting and clear coats.


I'm pretty slow. This took the whole weekend!

Now I have to wait to reassemble everything once I get my order from Roger.

Little hick up in this rear brake refurbish. The small rear left hard line is unavailable from Roger at 928Rus at this time. Maybe a 12 week wait from Germany. I don't really want to wait that long if I don't have to.

Are good condition USED hard lines possible?

Can these be made by a shop? What kind of shop would do this?

Rick,
If you don't absolutely require OE, they are easy to make. A few years ago, I had to make one for a '74 BMW 3.0CS I had. You can re-use the male connectors from the original. I have several feet of the copper tubing I used, which can be bent to proper shape when done carefully. I'll give you whatever length you need, plus a foot in case of error! You'll need to flare the end when cutting to proper length and shaping is done and connectors are on the tube. I can send it to you, or bring it to Carlisle, whichever works for you.
I'm away, but should be able to ship "as soon as I can find it" upon returning home tomorrow.

Gary Knox

Gary Knox wrote: ↑Thu Apr 03, 2025 11:25 am Rick,
If you don't absolutely require OE, they are easy to make. A few years ago, I had to make one for a '74 BMW 3.0CS I had. You can re-use the male connectors from the original. I have several feet of the copper tubing I used, which can be bent to proper shape when done carefully. I'll give you whatever length you need, plus a foot in case of error! You'll need to flare the end when cutting to proper length and shaping is done and connectors are on the tube. I can send it to you, or bring it to Carlisle, whichever works for you.
I'm away, but should be able to ship "as soon as I can find it" upon returning home tomorrow.

Gary Knox

Thank you Gary. But, the male connection at one end of the hard line is damaged (rounded nut). Can just these connectors be sourced?
Wouldn't I need a special tool to flair the ends?

I think I still have the flaring tool. I'll loan (or sell) it to you. Don't know about the connectors, but Mark Anderson might be able to supply one!

Getting on a plane soon, so may not be able to respond for the rest of the day.

WyattsRide wrote: ↑Thu Apr 03, 2025 11:55 am Can just these connectors be sourced?

Yes.

https://belmetric.com/fittings/brake-lines-fittings/

M10x1.0 IIRC, but check that.

WyattsRide wrote: ↑Thu Apr 03, 2025 11:55 am Wouldn't I need a special tool to flair the ends?

Yes. It's a bubble flare.

Belmetric also has "bend it yourself" pre-assembled lines. I don't know if any of them are the correct length nor how hard the tubing they use is to bend. Shipping might suck if long.

https://belmetric.com/4-75mm-brake-line ... ed-tubing/?

If none of those are close to the correct length...

If I have fittings left, I can make you one with easy-to-bend tubing. I will need the exact "straight" length. You will need to bend it to match your old one. Should be less than $50 including ground shipping if it fits in a "tube."

I will get back to everyone. I have a call into Mark at 928 International.

Thanks everyone!

All is good. I have a used line on it's way from 928 International!

This weekend I rebuilt the calipers, attached the hard line on the left side and put everything back together. Now I just have to bleed the lines.

Question though. The new rotors have a coating on them. I cleaned the surfaces with brake cleaner. But, I did not try to remove that grey coating. Should I have?

Also, the sensor ends are broken and will not stay in the pads. Can I just leave them loose for now?

WyattsRide wrote: ↑Mon Apr 14, 2025 1:46 pm This weekend I rebuilt the calipers, attached the hard line on the left side and put everything back together. Now I just have to bleed the lines.

Have two quarts of fluid on hand. It may take two-go'rounds to get all the air out of the lines.

WyattsRide wrote: ↑Mon Apr 14, 2025 1:46 pm Question though. The new rotors have a coating on them. I cleaned the surfaces with brake cleaner. But, I did not try to remove that grey coating. Should I have?

The brake pads will remove the coating. Follow the WSM bed-in procedure though. The brakes won't have full performance until the coating is removed.

WyattsRide wrote: ↑Mon Apr 14, 2025 1:46 pm Also, the sensor ends are broken and will not stay in the pads. Can I just leave them loose for now?

I wouldn't leave them "loose" as they may flop around and get caught in something. At a minimum zip tie them to something so they don't flop around.

You can also do what I and others - who check their pads regularly - have done: delete the warning contacts.

Procedure:
- take the old warning contacts and cut them an inch or so from where they connect to the wheel well harness.
- strip the insulator from the two wires
- twist the conductors together (or solder)
- apply a bit of heat shrink to clean up the connection

Don't do this if you rely on your pad warning system; order new warning contacts.

Thank you Dave!!

I don't think the rear sensors were ever attached. When I took off the calipers they were already just hanging out. I will zip them up out of the way. The front sensors are in correctly. That's how I figured the rears were broken and don't have the little additional slot to keep them in place.

The 85 is back on the road and braking beautifully!

Thanks to Ed R (linderpat) for helping me bleed the brakes. It took a couple sessions to finally get all the air out. I'm lucky to have Ed close.

Thanks to Dave and everyone else for the online help!