Front rotor replace
 

Looking to do the front rotors, pads etc for my 88. The tech articles say to remove the clip that holds the hard line to the flex but not sure how that is done. It doesn't seem to have a notch where it slides out.

I know there is an easy answer but Im missing something.

No clip there. Need to break the line

Now might be a good time to consider replacing the flex hoses. The attached active thread might be incentive.
I recently did my ‘87 and all the fittings came loose without issue.
http://forums.pelicanparts.com/porsche-911-technical-forum/1104936-brake-bleed-problem-83-911sc.html

As I recall you disconnect the hose at the caliper, release the clip and pull it through. Or if May be that you disconnect the hose from the hard line once you release the clamp.

It depends on how far you want/need to go..
 

You can unbolt the caliper from the strut and use a coat hanger to hang the caliper out of the way, giving you full access to the disc/hub assembly.

If the flex lines are original to your 88, it is probably time to replace them.

If you are ging to disconnect the steel/flex line and you have recently flushed the brake system, you might want to use a stick or bar of some kind to depress the brake pedal, so you dont completely gravity bleed that end of the brake system on to the floor, or into a container you have thoughtfully placed to collect the fluid. New fluid is cheap.

If the system is all still original, dont depress the brake pedal to the floor, or you might cut the MC seal on the trash/rust that has accumulated in the MC bore,over 40 years of use.

When replacing the disc on the hub, it is appropriate to torque the nuts/bolts, then repack/replace the bearings. I would take one step further by running a dial indicator on the rim of the disc to ensure that the run out is within spec, or have it trued. You could try unbolting the disc from the hub and rotating it one or two studs and rebolt/recheck the run out - if all else fails, have it trued on a brake lathe - I think the spec is .006-.008 run out max, but look it up.

good luck,
chris

Awesome guys, really appreciate it. I had forgotten it was such an ordeal. How on earth would you swap rotors in a racing situation back in the day? After several hours in the pits someone had to come back to the engineers and said "Nein!"
I got the pads and sensors done, that was easy.

I remember seeing this when you had the issue, thanks for the link!

A 'while you are there'....how are your front bearings/races? Not a hard job considering you'll have everything out in the open....

I will definitely check!

That clip is open on one end and slides into place with compression. Look on Pelican for a photo of a replacement and you'll see. Gentle with a flat head screw driver will coax it to slide off. Rubber brake lines are cheap consumables and an easy replacement - just make sure that you have the proper wrenches so you don't destroy the hard line fittings. I've looked at your photo again and don't see the slot so perhaps yours are a repurposed item from another car. The internet shows the slotted version for a 1988 911. You may have to remove the hard line in which case the rubber line will slide backwards out of the bracket. If you are keeping the car there's no time like to present to tackle the rubber lines.

Yeah no slot. I'm going to order the lines, block off the weekend and knock it out soon

Any tricks to the hub reinstall? I know if too tight it can bind and too loose it will wobble with the extra play...

When you first install the hub back in place after repacking grease (and possibly changing out bearings) tighten it up to seat everything then back it off to start your process. I do as the Bently's suggests. Tighten until the washer under the 'nut' assembly can be moved with a screw driver tip.
Myself, I tighten a tad more than that but the washer still moves.
You can do a quick check by mounting a tire and see if you have play l/r...

I was putting some parts from last years brake work away today and came across a new spare version of that very item. Triggered my memory that the back are notched and the front are as your appear. My front ones were rusty as was the hard line fittings. I ordered the lines from Porsche but only realized the clip was boogered when I separated the parts. Searched the part number and bought several from the local VW dealer. Interchangeable it appears. Cheaper and they were in stock.

Measure your rotors. If they are still in spec, many shops can turn them with the wheel on. I had mine done two years ago and they stop perfect.

Exactly. I got a nice scuff on them and they are within spec so at least good for now

Yeah these are strange, a clip with a hole in it. I have seen the others but not on this car...

You can remove the rotor/hub without removing the brake line from the caliper or this connection at the strut. The hard line can stand a bit of flexing, and after you have removed the outer bearing you have a bit of extra movement available to get the caliper (which you have unfastened) off.

Lately, I have taken to cutting a slot in the tab on the strut, mainly to facilitate taking the strut off and putting it back on, though it gives you more play for replacing a rotor. A zip tie works fine to hold things in place. Doing this kind of work without opening up any brake line fittings can save a lot of extra work.

If there is a down side, it would be that the line fittings have more time to rust or otherwise stick together, and when they need to be removed there is a tendency to blaspheme more.

That's a really good idea. Let me know if you have a pic somewhere that shows what you did.

There are two types of clips and both are used in Porsches.
On some hoses the fittings are different on each side and use a different clip.
Here some pictures

http://forums.pelicanparts.com/uploa...1636479287.jpg
http://forums.pelicanparts.com/uploa...1636479287.jpg
http://forums.pelicanparts.com/uploa...1636479287.JPG
http://forums.pelicanparts.com/uploa...1636479287.JPG
http://forums.pelicanparts.com/uploa...1636479287.JPG

Great pics! Thanks!!!

THS
I don't have a picture of what I modified, but I did modify your picture showing the approximate location of the cuts I made in the tab which holds the brake line stuff onto the strut. The slot just needs to be the width of the round brake line fitting.

I notched the tab top and bottom, thinking I could use a zip tie, but hadn't thought it through (or maybe needed a deeper notch), so I just zip tied around the strut after I had installed the two springy pieces.http://forums.pelicanparts.com/uploa...1636526543.jpg

With a little more thought, something a bit better could be devised. Drill two small holes and use safety wire maybe. I was in a hurry.

better would have been to (if at all) cut the notch at top.
Eather way you'll have to secure the brake hose to safely sitting in place.
in the racing days they did that and used wire wound araound the strut to fix that.

I myself changed the whole set up exactly due to this annoying detail that you cannot release the hose to move freely when working on the brakes (rotor/caliper)

click=> instead I made a custom brake hose with mounting adapter

Tighten until you feel a small play with the wheel on.

The old tighten until you lock up the wheel, to make sure its seated properly, then loosen 1/4 turn gets you pretty close.

This is a very elegant setup. I need to make sure I note your parts list. Well done and thanks for sharing this.

Wait, are you saying the 911 is so convoluted that you need to grind and break brake lines just to change a damn rotor?

No, you just "flex" the hardline...

Yes, while flexing a hardline is an option, it isn't something that most people feel comfortable with or think is worth the risk. Clearly, changing rotors was not designed as a 10-minute job by the engineers at Porsche as it is with most other cars. Porsche's idiosyncrasies are certainly not a secret around here. What's so rewarding is seeing how those of us have improved upon those designs with clever updates, elegant simplification, and downright artistry.

I'm not sure this is an idiosyncrasie. Changing rotors isn't something you do every year or every second or third. cracking the lines and having to blled the brakes is not a big thing, bleeding the breaks should be done far more often than changing rotors.

the wear ususally doesn't require regular work on either pads, rotor or bearings any often.

BUT, if you have to, then it' an annoying set up to deal with.
In my opinion THIS for once could have been over-engineered. But no.

The mere fact, that you have to disassemble the seating of a bearing (the outer one) to pull the rotor-hub-unit is "stupid" (excuse my French).
But that was a standard back then (Mercedes, BMW...)

And to be able tu pull the rotor-hub-unit the caliper mus give way.
This is only possible if a) you remove the caliper by separating the brake line (requires bleeding later) or -what 99% do- is b) to bend/flex the hardline some bit.
Once rotor-hub-unit pulled you mount the caliper with a bolt just for time being.

With some common sence both options don't seem to be very optimal (to say the least)

One could say that pulling the hub gives you the possibility to inspect the grease, bearings and the spindle... granted.

but bending/flexing a break line is against my personal understanding of security.

That is why I chose to go for a full-length braided brake hose.

Btw, the idea is not new... back in the days that was a common setup for 911 racing cars

Alternative -if absolutely wanting to keep the soft and hardline- is to use the attaching bracket from elephant racing.
Designed for coil-over struts but you can just use it as is with your Boge or Bilstein, Koni

https://www.elephantracing.com/911/coilover-kits-parts-for-911/coilover-conversion-kits/coilover-brake-line-support-bracket-kit/

https://www.elephantracing.com/wp-co..._plate_kit.jpg

If the wheel assembly has to come off, I bleed the front brake system until it's empty in order to avoid the mess of lines dripping everywhere.

I bleed the brakes between every track event as is.

I like the little bracket idea that Flojo has on his car. This way, it decouples the mount from the strut and with one bolt you can move the assembly around and retain the hard line if you want.

Pusha down the besked pedal slightly with something against the seat and you van crack open the lines without any dripping..

Your racing routine could be very helpful here. While most of us don't do that mutch that often, I'm sure you have come up with a good many do's and don'ts that would be very helpful here.

If you race/track your air cooled 911 much, you will change rotors way way more often than you would on a sensibly driven street car. So for that, making pulling a rotor easier is valuable. Especially if you have to do the change at the track? I'm not talking about endurance racers, who figure out ways to change rotors during a pit stop.

I've bent my hard lines many times. Nary a problem. But it is one more thing you at least wonder about, and fiddle with to do a minimum of bending.

With the "depress the brake pedal to close the brake fluid reservoir intake in the master cylinder" technique, you can, indeed, lose basically no brake fluid. I've just reconnected the brake line (I put home made plugs from spare brake fittings into each open end) and gone back to driving with no discernible softening of the pedal. Bleeding is, of course, the preferred practice.

However, I have had trouble from time to time with loosening fittings. The ones to the calipers typically come apart easily. But the others, which don't come apart as often, sometimes have been seriously stuck. Even having proper brake fitting wrenches sometimes hasn't worked as I hoped. Last time I changed one of the hard lines I had to cut it off short so I could get a socket over the end fitting. It had been on since 1976. So not having to unscrew fittings can have a benefit. To be sure, if I had ever opened the fittings just to apply a little anti-seize, maybe they would always be easy to unscrew.

exactly. you got it

I know the trick.

Unfortunately, I might only get an hour or two to work on the car at a time. For example, replacing the front wheel bearings took me a couple hours spread over a couple nights.

I don't want to leave the brake pedal slightly depressed that whole time. It might be fine, but I don't want to test that. I could reconnect the lines, sure, but with the calipers off it's an opportunity to clean and inspect them.

I feel obliged to say I don't race (yet), but spend as much time doing driver education events as I can.

I can write up my checklist.

One don't I'll add now, is don't leave your brake system pressurized by a Motive bleeder and go eat dinner. Even running it dry, 10 PSI is enough to slowly weep brake fluid out of hoses that attach the reservoir to the master cylinder. :o