Order of Operations for Full Brake and Front Wheel Bearing Job

[getluky]

So I've finally collected all the parts for a pretty involved brake job. Car in question is a 1987 911 Targa that's seen its share of neglect. I'm hoping to replace the pads, rotors, brake lines, and front wheel bearings, rebuild the calipers, and put in new brake fluid.

I've been reading up on individual posts about each of these jobs but would love a bit of advice as to which order to tackle everything in. The brake fluid in there is pretty dirty right now, plus the dust boots on the front caliper pistons are completely shot. Also, i've already got the pads replaced (after which I found that I needed to do more), but am willing to put the old ones back in if it matters. I've never done any of this, so please bear with me as I try to assemble an order of operations that makes sense.

Here's what i'm planning so far - can you guys give comments?

Act I: Get Dirty Brake Fluid Out

1. Drain dirty fluid from reservoir
2. Clean up inner reservoir a bit with a terry cloth towel
3. Fill reservoir with new brake fluid (gonna use an intermediate here, don't want to waste the ATE Blue that I have for the final bleed)
4. Do a bleed with the pressure bleeder to flush the old fluid
5. Siphon out a little fluid from reservoir to prevent overflow

Act II: Rear Brakes

1. Block brake pedal at 1" depth, put drip pan below brake line, remove pads
2. Disconnect hard brake line fitting at back of caliper with flare wrench
3. Disconnect flexible brake line clips - I rotated 45 deg with a counterhold flare wrench at the hard brake line fitting since these were tight, and that let me get it off. Once the brake line clips are off, you can push the connection backwards and that lets you get a 18mm counterheld flare wrench on the flexible brake line fitting.
4. Remove caliper mounting blots and remove caliper (the lower bolt was tricky, people seem to build different contraptions for this)
5. Remove rotor to hub screws and remove rotor
6. Remove fitting on hard brake line to flexible brake line, disconnect hard brake line
7. Disconnect flexible brake line
8. Install new flexible brake line
9. Connect brake line clips
10. Reattach hard brake line fitting to flexible brake line
11. Rebuild caliper (steps not listed)
12. Install new rotor + screw onto hub, 5 Nm
13. Install caliper via mounting bolts, 60 Nm
14. Attach hard brake line fitting to rear of caliper
15. Check caliper piston alignment
16. Reinstall pads, clips, etc.
17. Repeat for opposite side

Act III: Front brakes + bearings

1. Remove brake pads
2. Disconnect flexible brake hose from hard brake line at bottom of strut
3. Disconnect metal brake line from rear of caliper
4. Remove caliper mounting blots and remove caliper
5. Try to remove dust cap
6. Loosen 6mm allen clamping screw in wheel bearing lock, unscrew and remove lock nut
7. Remove rotor and hub from spindle
8. Remove flexible brake line clips
9. Remove and replace flexible brake line and clips
10. Remove 8mm bolts mounting brake rotor to hub
11. Tap hub out of rotor with mallet
12. Remove grease seal and inner wheel bearing from hub (not sure if this is a hard part or if it just comes out)
13. Clean hub assembly, esp. rotor mounting surface
14. Heat hub assembly up, and drive wheel bearing outer races (noted that Bentley manual seems to recommend driving outer races from the hub using drift pin prior to heating, but i'll heat it anyway in the old bbq as per forum recs)
15. Pack new wheel bearings with grease, lightly coat races, and put in freezer
16. Heat hub assembly, and press new (cold) inner+outer races into hub
17. Lightly coat races with bearing grease
18. Insert inner bearing into race and put in new inner seal
19. Apply grease on top of inner seal
20. Reinstall new rotor onto hub, tighten 8mm bolts to 23 Nm
21. Carefully slide hub + rotor assembly onto spindle
22. Install outer wheel bearing, thrust washer, and wheel bearing lock nut
23. Tighten lock nut while rotating brake rotor
24. Adjust wheel bearing play - while rotating hub assembly, tighten lock nut slowly until thrust washer can barely be moved back and forth
25. Tighten clamping screw to 15Nm
26. Fill grease cap with 10g grease and install
27. Rebuild caliper using special procedure
28. Reinstall caliper and tighten caliper mounting bolts to 70 Nm
29. Reinstall hard brake line onto caliper
30. Reconnect hard brake line and flexible brake line
31. Check caliper piston alignment
32. Reinstall brake pads
33. Repeat for opposite side

Act IV: Brake Fluid and Test

1. Top off reservoir
2. Pump brake pedal a few times to seat pistons
3. Bleed brakes in standard pattern
4. Go out for some low-speed driving, test brakes thoroughly, slowly building up speed and giving time between heavy braking to allow for cooldown

Whew, that was a mouthful! Although the list of steps seems kinda daunting, I hope I can get through this in the next week of slow progress. If you spot any inconsistencies or big problems in my list, please do let me know. I think the scariest thing is getting all the way through the job without doing a test. If there is a good way to split this up, then please let me know. On one hand, I want to get things done efficiently, but on the other hand, I don't want to run any big risks. Thanks in advance for any feedback you've got!

[getluky]

bump... still looking for feedback.

[RWebb]

I would save the refill of brake fluid to late in the operation.

[getluky]

Ok, I can do that. Is that because the fluid won't be flushed through the system at all during the procedure?

[KTL]

Before you start, put some good penetrating lubricant on the brake line fittings. These are notoriously difficult to break free, due to the corrosion and protective coating. Soak them for a day or so if possible and then a small amount of heat if necessary. Some times the tube nut just won't come free from the tubing and the line is ruined. Be prepared to possibly buy some replacement hard lines!

Take your time packing the bearings with grease if you don't have a bearing packer. Local parts store might have one- its a pair of concentric cones with a zerk fitting to force the grease over & through the bearing. If no packer, fill your palm with a large blob of grease and knead it into the rollers and gaps in the cage between the race & rollers. Take your time and work the rollers, spin the cage & race for a few minutes while you knead to make sure the bearing assembly is well filled with grease.

Be sure to gently clean the mounting surface of the rotor on the wheel hubs in front. Crud and paint from the rotor hat can make this surface uneven for the new rotor. Then you'll have some pulsing from the brakes. It's actually advisable to check the rotor for runout after you install everything back together on the car (before you bleed the brakes) and rotate the the rotor ("clock" it) on the hub if you get too much runout. Runout spec is typically 0.002" I believe.

Since you're rebuilding your calipers, you'll want to install the pads so they're really tight fitting to get into the calipers. With the new seals in the calipers, you'll have pistons that want to retract more than usual. This will leave a slight gap between the piston, pad and rotor and what you'll end up with is a brake pedal with a lot of travel. You might think you have air in the system and needlessly bleed the brakes again. At each caliper, one at a time, extend the pistons out a bit and push them back in so that you have a nice tight fit where the pads will have to be muscled into the caliper a bit. This will prevent the low/pumping-up-the-pedal condition that typically occurs with new caliper piston seals.

Finally, i'd suggest Valvoline Synpower brake fluid if you want to pre-fill with something other than Ate Blue. The Valvoline is a good fluid with a wet boiling point near that of the Ate. So you won't lose much heat resistance when the two fluids mix.

[rusnak]

excellent advice above. Here's a tool that will do the brake piston retraction. You install the pads with pins, without the spring. This tool goes between the brake pads, and you "spread" the brake pads just until the pads are wide enough apart to slide the caliper over the rotor.




and you might want to make a brake piston alignment template.

[Superman]

Even if I were going to replace the flexible brake hoses, I would still rebuild the calipers before removing them. For example, on a front wheel I would remove the wheel then detach the caliper and hang it using a coat hanger. I would replace the bearing races and set the hub aside. Then I would push the caliper pistons out using the brake pedal. (I would have probably bled the brakes by this time, so that when I am finished rebuilding a caliper, any brake fluid introduced after that would be clean brake fluid) Replace the rubber and reinstall the piston. Hold one piston in with a c-clamp vise grip while the other is pushed out and rebuilt. When that caliper is finished, I would then remove it from the brake hose, remove the brake hose and replace. Caliper pistons are easier to remove using the brake pedal than pressurized air. Safer too.

[RWebb]

also, don't rebuild all 4 calipers at once...

[getluky]

I'm stuck trying to get the rear hard brake line fitting off. I can't get a grip on the 18mm connection on the opposite side of the fitting to counterhold it. Do I need to get the pressure clip off first? Any tips on how to remove that, because whenever I pull on it, it seems to be pulling the hard brake line that goes to the caliper, and I don't want to bend it if I can avoid it.

[getluky]

Possibly related: even though i've unscrewed the fitting going into the caliper, I can't seem to fudge the hard line out of the caliper. Is it safe to try and bend the hard line a bit to get it out, or do most people remove the caliper first and/or the other end of the hard line?

[Superman]

If you remove the clip on the trailing arm, the hard line can simply be pushed through the opening and then the caliper will sit nicely right on the trailing arm where you can rebuild the caliper there. I have removed plenty of pistons using compressed air and I don't do it any more. I use the hydraulic pressure of the system. Much easier and less exciting.

You MUST use a flare nut wrench on brake line fittings. If I HAD to, I would use compressed air to remove a caliper piston but I would probably not even try to remove the line fittings without a flare nut wrench.

[getluky]

Thanks, Superman. I was able to remove the clip on the trailing arm by rotating it 45 deg while counterholding the hard line fitting, then pulling it out was much easier with the additional purchase I could get on the tab. Once I got that out, I did pull the entire hard line off. The caliper really needs a good cleaning, so I did want to get it off of the trailing arm where I could use brake cleaner on it. If I already siphoned off some brake fluid from the reservoir, wouldn't I have to put some back in to use the hydraulic pressure to get the pistons out? And I still need to block the pistons with some thin wood so they don't bottom out, right?

Now i'm stuck on the lower caliper mounting bolt. Any tips on getting that thing off? I've tried a long flex ratcheting wrench, and I can't fit my 1/2" breaker bar with 19mm socket into that tiny space. I hit it with some PB Blaster while I try and think of what to do.

[rusnak]

you can get a flex 3/8" ratchet in there, or use two combination wrenches locked together for more leverage. You break them loose, and then switch to fingers. If you try to loosen the bolt all the way with a wrench, the wrench will get trapped between the caliper and your trailing arm. If necessary, wiggle the caliper to help the bolt along. Remember the lefty loosy righty tighty convention. Have faith, it'll come off.

[Superman]

Do not let the brake fluid reservoir get less than half full during these operations. If you are going to press a piston back into a caliper, then you will displace fluid and potentially overflow it at the reservoir. In this case, you would remove some fluid from the reservoir. But otherwise, you need to keep the reservoir topped off. Never let it run dry. If you do, you will need to bleed the master cylinder. Sometimes that is a difficult job.

So again, I say clean the reservoir and fill it with clean fluid. Let gravity do the bleeding for you. You WILL introduce air into the system, so you will need to bleed that air out at each caliper.

If you use the hydraulic system to remove the pistons then no, you don't need to place a block of wood in there. The piston will not BLOW out like it does when you use air. It will slowly push out. You will need to hold one piston in place while you remove the other. To do this, use a c-clamp vise grip plier. A set of three or four different sizes of this tool can be found at Harbor Freight Tools for about the same price as a meal at McDonalds. Very nice tool when working on brake calipers.

Keep an eagle eye on that reservoir.

Again, I would probably make sure the system is running clear before I reinstall a piston. That way, the fluid entering your caliper is clean. After rebuilding, I would probably bolt the caliper back onto the trailing arm, and THEN remove and replace the brake line. And I would use a flare nut wrench.

[Superman]

I would not be queazy about using a long 19mm regular wrench and smacking it with a heavy deadblow hammer.

[rusnak]

I could be wrong about this, but I think more people do damage to their master cylinder by pushing on the pedal with open brake lines than by letting air in the lines and leaving the brake pedal alone. The reason is that there is dirt in the system everywhere, no point in pretending that there isn't, and when you push the mc beyond it's normal range of motion, you can get dirt to score the mc or the bore, or abraid the o-ring.

I know everyone does things differently, and to each his own. This is why bleeding brakes is such as black art.

[KTL]

Originally Posted by Superman

I would not be queazy about using a long 19mm regular wrench and smacking it with a heavy deadblow hammer.

Same here. 19mm box-end 12 pt wrench and a big hammer. I love my Truper 4 lb mini sledge.

[rick-l]

WOW that plan is nice but you're just going to end up taking it all apart and putting it back together in whatever order you can.

I did the same thing not long ago (minus the bearings) and had little trouble. I did all 4 wheel calipers at the same time and just let the fluid run out. I also used sil-glyde.

Only setback: Get half the rear dust boot on and clamp a piece of wood over it. Then work the other half on with a large flat blade screwdriver.

[Superman]

I'm fairly proud of my hammer collection. Of course, Superman doesn't actually need hammers but I do have a drawer-full. The one I would use on a wrench is the rubber, shot-filled deadblow hammer. I think it goes about six pounds or so.

Yes, operating a master cylinder beyond its normal movement range is risky. Actually, its normal movement range is almost nothing. It doesn't move as much as it simply applies pressure.

[getluky]

OK guys, I finally got the two mounting bolts off. I made an embarrassingly bad contraption to do it, though - I ended up using a 3/8" ratchet with 19mm socket, and got a large socket on top of my 1/2" breaker bar to kind of lock around the end of the ratchet. Had about 20+ inches of leverage and it still took a huge effort to break. Couldn't fit a straight cheater pipe around the jack stand I had at the torsion bar, but this thing finally got the bolt loose. There's a lot of crud in the threads too.

Now that i've proven to myself that I can take the thing apart, I feel a lot more confident that I can actually get this job done. Thank you so much for the constant help.

After a small breather, i'm going to clean up the threads in all the stuff I removed, then reattach and try bleeding out the old fluid with some new cheap DOT 3 Valvoline brake fluid I got. Once I do that, I think i'll try out Superman's procedure of using the hydraulic system to push out the pistons.

One question, though - how do you clean the brake caliper thoroughly with brake cleaner if it's still attached? Do you just spray it on and brush with a wire brush?

Oh, and FYI, I used flare wrenches at all the brake line fittings, thanks.