Series 1 Brakes

CD's with documentationElectronic distributor
mudds
Posts: 3
Joined: 05 Apr 2021, 15:43

Series 1 Brakes

Unread post by mudds »

Can anyone help? I have a 1970 series 1 zagato, recently returned from a short journey and found the front brakes sticking, I removed the calipers and a lot of debris and refitted, unfortunately I allowed the brake fluid to get low in the MC. The problem is I cannot remove the air in the front brakes, have tried all brake bleeding methods without success. The MC was reconditioned by Omicron about 3 years ago at great expense, have probably driven less than a 1K miles since then, no leaks in the system, new fluid, refilled a number of times, where does the air come from?
Huib
Site Admin
Posts: 1778
Joined: 17 Dec 2008, 10:12

Re: Series 1 Brakes

Unread post by Huib »

Are you sure it is air? We usually have no problems bleeding Fulvia brakes.

Could it be excessive retraction? It is easy to measure. It should always be measured when doing a Dunlop brake job. It should be less than 0.15 mm. I like to keep it under 0.10 mm.

Are the discs wobbling? The manual specifies max 0.15 mm of wobble. I like to keep it under 30 micron.

Did you change the pads? If not they may be in different position and need long run in. If you have new pads they may be too soft and compress.
mudds
Posts: 3
Joined: 05 Apr 2021, 15:43

Re: Series 1 Brakes

Unread post by mudds »

Ok Huib, will remove the calipers and double check everything, let you know how things go.
John.
Huib
Site Admin
Posts: 1778
Joined: 17 Dec 2008, 10:12

Re: Series 1 Brakes

Unread post by Huib »

I don't see any reason to remove the callipers at the moment.

Just step on the brake hard. Release the pedal and measure the gap between disc and pad with a feeler gauge.

Put a micrometer to the back 9f the piston in the wheel brake cilinders. Let someone step 9n the pedal and release. See how much the piston comes back.

Put a micrometer to the disc near the edge and turn the disc.
bmarler
Posts: 110
Joined: 22 Dec 2008, 17:33

Re: Series 1 Brakes

Unread post by bmarler »

Just a thought, did you bleed the master before bleeding the calipers?
mudds
Posts: 3
Joined: 05 Apr 2021, 15:43

Re: Series 1 Brakes

Unread post by mudds »

Update, checked retraction gap, ok, am using the existing pads. I have a remote servo fitted with flexible pipes, i sealed off the incomer to check the MC, result a solid pedal. Getting know where so decided to check the calipers, removed pistons, cleaned and checked seals, reinstated, carried out a gravity bleed and hey presto I now have a reasonably solid pedal. So none the wiser.
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