UKPOC forums

After my good MOT news on Thursday, I've struck up today, and have no brakes
New brake calipers were fitted at the garage and I've driven the 10 miles back home no problem.
Got in today, started , put in reverse, and brake pedal goes straight to the floor.
I've visually inspected for any fluid leaks, and brake reservoir is at the correct fluid level. When the engine is running there is no pedal resistance at all, engine off and there is some resistance. Is this a problem relating to the recent work or a coincidence

Sounds like the seals in the master cylinder are weak.

Kit

Kit wrote: ↑

Sat Oct 31, 2020 4:42 pm

Sounds like the seals in the master cylinder are weak.

Kit

Right ok cheers Duncan. I don't have one of those, do you happen to have one in stock that I could purchase please

Yep ,

Drop us your address,& I put it in the post

Kit

This is the brake master cylinder





I would recommend replacing the link hose to the clutch master cylinder, with new hose & clips. Remember, the clutch will need bleeding as well

I’ll clean it up before I send it.

Kit

Fantastic Duncan , that is much appreciated mate , let me know costs and I'll send it over to you and then I'll get it towed over to the garage.

A lifetime in 'maintenance' convinced me of the truth of 'the inverted ' bathtub curve' and , wherever possible, 'if it ain't broke, don't fix it' theory.
Essentially , if things go wrong it will be directly after (faulty) 'maintenance' and at 'end of useful life'.
So, coincidence that your brakes failed after maintenance, following 'years' of faultless performance ?
Nope.

I think I have an explanation for this master cylinder failure.
When the calipers were bled the full stroke of the pedal was used, which never happens in normal driving. The rubbers in the master cylinder moved over a part of the bore that hasn't been touched in a long time and has some rusting (brake fluid absorbs water), this rust digs grooves in the rubbers and they no longer seal.
I try to use no more than half the pedal travel when bleeding brakes.

Thinking about what David said,
Would it be a good to the replace the seals within the master cylinder, before swapping them .
That way you’re know that they ‘good’

Repair kit’s are about £10 from Rockauto’s + shipping & tax

I could get you a set, & fit them. Before I post to you, but that could take a few weeks.

Kit

Kit wrote: ↑

Sun Nov 01, 2020 1:12 pm

Thinking about what David said,
Would it be a good to the replace the seals within the master cylinder, before swapping them .
That way you’re know that they ‘good’

Repair kit’s are about £10 from Rockauto’s + shipping & tax

I could get you a set, & fit them. Before I post to you, but that could take a few weeks.

Kit

That would be fantastic and very much appreciated Duncan , not a problem on timescale at all. Yes, if you don't mind ordering as you know what's what and let me know how much I owe you and ill get it sent straight over. Thank you