What I learnt from doing my front brakes

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jb
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What I learnt from doing my front brakes

Post by jb »

I have just replaced my front discs with new pads and had the the callipers rebuilt by classiccar.

The discs
Use a magnet to extract the washer and bearing when taking the disc off as it will save the bearing bouncing on the floor on the the newspaper you put there?
When separating or assembling the disc wedge a ring spanner on the inside of the disc rather than trying to use two sockets like the pelican illustration.

The callipers
I think it would have been better to remove the banjo bolt rather than undoing the pipe from the socket piece. However my socket pieces seemed very unhappy about going onto the pipes when I tried to put it back together so I replaced them both so perhaps that was a good thing in the end.

If you put in new pads at the back after you send off the front callipers then remember to put containers at the front to catch the brake fluid from the open connections at the front.

Bleeding
If you use a pressure system and need to block off the reservoir breather pipe with mole grips or similar and the breather is old and brittle then wrap a cloth around it and soak it in hot water to soften it first and put the grips onto the cloth rather than direct onto the pipe.
Make sure you have four 7mm ring spanners one for each bleed nipple and put the spanner on first then put on the bleed pipe which also needs to be warmed. (I used a wine bottle full of boiling water wrapped in bubble wrap).
I think I went round three times and then went for a drive and went round one more time the next day I also wedged the brake pedal down overnight because someone suggested that it helped do something positive.

Finally cat-litter does an amazing job of cleaning up the mess I made on the garage floor with all that brake fluid.

Not sure I would want to do it again though.
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911hillclimber
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Re: What I learnt from doing my front brakes

Post by 911hillclimber »

Only 3 laps around the brake nipples?
You did well in my experience. Evil job.

Pressurising the system (ie overnight) I think only disperses any air into the fluid temporarily, or so I'm told, and gives a false feeling of a solid pedal!

Only way to bleed an early 911 is to train your wife or mistress to sit in there and go up and down to your beckoning!
With her foot of course... :)
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Re: What I learnt from doing my front brakes

Post by mycar »

Good to see you're keeping your hand in Jb, makes me think I should take something to pieces and put it back together again. :)
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jb
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Re: What I learnt from doing my front brakes

Post by jb »

911hillclimber wrote:Only 3 laps around the brake nipples?
You did well in my experience. Evil job.
Graham it took hours. First time I put the bleed tubes on first and scrabbled around underneath trying to use the open ended spanner. Hence my note to myself about putting the ring spanner on before the bleed tube. Even the last time around took ages as the ring spanner was not alway fully located or came into conflict with the tyre. I only jacked up the back so I could get my hand in over the tyre but I should have jacked it up and taken all four wheels off so I could see what I was doing although I am very uneasy about being fully underneath the car even when it is on stands.
The good news is that the pedal is firm and it is where it should be although braking hard does result in a fair bit of travel. Maybe because all the new pads and discs not yet happy with each other.
mycar wrote:Good to see you're keeping your hand in Jb, makes me think I should take something to pieces and put it back together again. :)
Thanks and good luck with that Mike!

Actually I seem to have come a full circle.
When I was young I had to fix things because I had no money and it was quicker and less hassle to do it myself.
Later I had more money and less time so I often got someone else to do it - mainly Chris Turner.
Now I am retired I have less money and more time and poor Chris is not an option so for me so the options are to do it myself or take it to Tuthills which is a bit of a mission.
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roy mawbey
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Re: What I learnt from doing my front brakes

Post by roy mawbey »

There is a sense of achievement when you manage to find the easiest way to complete a job you would have normally given to someone else. It does get harder laying on garage floors especially when its cold and thinking what if I end up with everything in pieces and the knowledge it would be difficult to get anyone to visit to complete it.

Its nice too JB you put some info on for others with a similar car to consider. These pointers can save people a lot of time and effort.

When I bought my 356 in the 60's I had no option but to do it myself, then sure later in life I could have paid out but almost liked the fact I could do it myself and the relative simplicity of the 356 allowed this to happen. But the 911 would have me thinking again about doing everything in fact I already know it would stop me in my tracks!

I did find the last major job for me on the 356 was changing the rear wheel bearing. Sounds easy but when you have make a special puller and you need inspection gear like micrometers and vernier gauge's then it starts to make realize without having all this and the gear to torque the rear nut to 400ft/lb and be fit enough crawl around it, would be that much harder.

So you did well on the brakes well done!

Roy
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Re: What I learnt from doing my front brakes

Post by Chris_911 »

From my experience I would not use the 'pump the pedal' method for bleeding brakes. The problem is that in doing this the brake mechanism, in particular the master cylinder, is exercised over a far greater travel than it would see in normal operation. This can cause the seals to be damaged by corrosion in the master cylinder.

This happened to me the one time I couldn't be bothered to get the pressure bleeder out and I ended up with a leaking master cylinder.
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