MASTER CYLINDER SEALS BLOWN?

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Justin
Posts: 366
Joined: 31 Jul 2008 12:18 pm
Location: Plymouth

MASTER CYLINDER SEALS BLOWN?

Post by Justin » 18 Feb 2012 02:22 pm

On Thursday my local cheap mechanic replaced my front o/s wheel bearing for me which meant disconnecting the front brake caliper. My brakes are now really spongey when I first start the car in the morning and remain much softer than before throughout the day. I took the car back to him on Saturday and he said it wouldnt have anything to do with him disconnecting my front brake.

A friend of mine who's good with cars seems to think that my cheap mechanic should have removed the filler cap on the brake fluid reservoir (which he didnt) before removing the brake caliper and that the following probably happened: The piston was pulled back in order to remove the front brake caliper causing the brake fluid in the reservoir to rise, which in turn has blown the seals inside the master cylinder, just because the filler cap wasnt removed first!

My haynes manual says the opposite and that you should remove the cap, place a piece of polythene sheeting over the opening, then refit the cap to prevent excessive loss of brake fluid when the caliper is removed?

WHO IS RIGHT, MY FRIEND OR THE HAYNES MANUAL?...

Any ideas/advice/suggestions will be gratefully recieved?...
Last edited by Justin on 19 Feb 2012 11:14 pm, edited 4 times in total.
1988 340 1.4 DL

(I suffer with O.C.D. which makes me obsessed with fine detail)

(Diagrams or photos are far more helpful to me when it comes to cars)

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L14MNP
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Joined: 26 May 2010 09:15 pm
Location: Sunderland/Durham

Re: BRAKES SUDDENLY A LOT SPONGIER!

Post by L14MNP » 18 Feb 2012 05:05 pm

When you say disconnected, do you mean the caliper was unbolted from the upright, or it was unbolted as well as the brake flexi hose was removed? I'd guess he's took it right off (no idea why) and then has bled the brakes poorly, or again my assumption would be not at all!
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Justin
Posts: 366
Joined: 31 Jul 2008 12:18 pm
Location: Plymouth

Re: BRAKES SUDDENLY A LOT SPONGIER!

Post by Justin » 18 Feb 2012 05:40 pm

L14MNP wrote:When you say disconnected, do you mean the caliper was unbolted from the upright, or it was unbolted as well as the brake flexi hose was removed? I'd guess he's took it right off (no idea why) and then has bled the brakes poorly, or again my assumption would be not at all!
He only unbolted the caliper from the upright and didnt remove the brake flexi hose so no need to bleed the system. I think its possible to replace the wheel bearing without having to detach the brake flexi hose, which is what he did. It feels as if I have an airlock but I dont see how as none of the brake fluid lubricating system has been detached either when I replaced my brake shoes or when the wheel bearing was done on Thursday!!
1988 340 1.4 DL

(I suffer with O.C.D. which makes me obsessed with fine detail)

(Diagrams or photos are far more helpful to me when it comes to cars)

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