Disco 1 Brake master cylinder failing ?

mr glee · Oct 24, 2021

On the journey home last night wife said that twice the brake pedal went down further than normal and brakes and were poor the rest of the journey brakes were normal have checked for leaks and level at max. master cylinder failing?.
97 with abs (turned off)

kevstar · Oct 24, 2021

air in the system, brake fluid needs replaced.?? Vacuum pump???

discool · Oct 26, 2021

mr glee said:
On the journey home last night wife said that twice the brake pedal went down further than normal and brakes and were poor the rest of the journey brakes were normal have checked for leaks and level at max. master cylinder failing?.
97 with abs (turned off)

To add to the list stated above its also one symptom of overheating brakes (brake fade), aso fluid and possibly brake pad replacements may be required.

mr glee · Oct 26, 2021

discool said:
To add to the list stated above its also one symptom of overheating brakes (brake fade), aso fluid and possibly brake pad replacements may be required.

Removed front pad as could see metal filings in the dust outside pad looked good but the inside may be due for replacement.

N/S caliper pistons all rusted up got them to move again but pulled the dust seals out for the cost will replace caliper.
O/s both pads have a strange step on the outside edge fitted incorrectly or other issue?.

kevstar · Oct 26, 2021

mr glee said:
Removed front pad as could see metal filings in the dust outside pad looked good but the inside may be due for replacement.
View attachment 251236
N/S caliper pistons all rusted up got them to move again but pulled the dust seals out for the cost will replace caliper.
O/s both pads have a strange step on the outside edge fitted incorrectly or other issue?.
View attachment 251237

Looking at the pads your disc is rusted on the outer edge, youd be as well throwing a set of discs
on as the new pads will bed into the same shape as the old ones & your not getting 100% pad
contact to disc & whilst your there you might as well chuck new wheel bearings in I use Timken.
Good luck getting the caliper bolts out best to buy a set of them too & you'll need a multihex socket.

mr glee · Oct 27, 2021

Cheers keV I had these off last year to do the hub seals I'm all tooled up.
Never seen it before but I would say the friction material separated from the back plate hence the excessive pedal travel and poor brakes while the pistons moved to take up the gap surface is rusty and the only contact area was the very bottom edge.

kevstar · Oct 27, 2021

mr glee said:
Cheers keV I had these off last year to do the hub seals I'm all tooled up.
Never seen it before but I would say the friction material separated from the back plate hence the excessive pedal travel and poor brakes while the pistons moved to take up the gap surface is rusty and the only contact area was the very bottom edge.
View attachment 251322

Ah cool good lad. Ive seen that loads of times when I was in the garage trade, ive also seen the pistons
pop out some scary sh!t tbh.

Disco 1 Brake master cylinder failing ?

mr glee

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kevstar

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discool

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mr glee

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kevstar

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mr glee

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kevstar

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