Emulsified/Melted Master Cylinder Rubber Plunger Seal

[Colin]

I'll find a block of wood or similar . . . but if that works and the system's bled, if I stamp on the brakes in traffic, what's to stop it jamming up again . . . ? (I'm sure I'm overthinking all this!) Best, C.

[johny]

Because the piston cant travel that far well not unless somethings gone seriously wrong with your brakes (burst hose, disintegrated brake pad or shoe, low fluid level etc). You'll only be using the part of the bore youve always used and anyway the back pressure in the system once pressed will always push the piston back👍

[Colin]

Cheers Johny,

Crossing fingers . . . 😉

Best, C.

[Mjit]

I take it you lubricated the new rubber seals with brake fluid while asembling?  The lip of the big seal especially need some lubrication as it's whole point is to NOT let fluid past so could be a bit 'sticky' in the boar initially if assembled dry.

And for the Eezibleed those are the symptoms of a non-sealing cap.  If everything's sealing properly you shouldn't hear any air escaping anywhere and shouldn't run out of air in the tyre as you only actually use a couple of master cylinder resevoir's worth - too much air/pressure in the tyre is the bigger risk as it can blow the cap off and you get a little erruption of brake fluid when it does!

[Colin]

Hi Mjit,

I completely agree with everything you have said. I faffed with Eezi-bleed, worked out I'd originally (1984!) put the incorrect Reservoir lid on. And after trying with that, and still getting fluid spitting out of it, worked out it needed a different lid sealing washer. Plus a less-than 20psi tyre rating seemed to lose all its air to the point that I then had to keep re-inflating it a bit. I lost the will, really . . . 

As far as the large cylibnder seal is concerned, there was enough residue fluid to have the internals re-installed. I have removed the internals again, this morning, lubed the lip and the cylinder internal walls, re-installed. At a certain (high) level of pushing in (compressing internals within the cylinder), it will stick, whilst less so from a lower level pressure of pressurisation. The job has to be done, so I'll keep trying . . . 😉

Cheers for now, Best, C.

[Pete Lewis]

of all the various   help accessories i have over the years used >>

I use a size 10   down quick back slow if you fancy nipping up the bleed screw at the bottom of the down stroke thats up to you 

this works without frustrations or spillages  

always keep the catch bottle up higher than the brake 

this  keeps the tube charged 

Pete

 

[Colin]

Folks:- so having re-fitted the internals as I had re-built them, lubed heavily and, out of madness, continuing to pressurise the piston & internals, I found most of the time there was a small delay in the internals & piston returning to resting position in the cylinder after being pushed in. Once in several 'pushes', the internals stayed in - and up - the cylinder. Not happy with this, off to a local mechanic chap I went. He confirmed my reconstruction was all good and the movement of the internals not right. We both concluded the middle seal (8) was just too tight. Fortunately, I had another repair kit and swopped it for the tight unit & ditched the tight unit so I can never use it again. Immediately, there was a movement that allowed an instant return of the internal piston when pressure released. On that basis and that being more normal as I recalled from my previously completely successful work of this ilk, I refitted the M/C and bled the system - successfully. Quite an eye-opener, this, for me. I've never experienced having a duff, overtight seal on these cylinders (identical brake & clutch & brake), knew it wasn't right,  but just needed my hand-held to confirm it was not anything I had done! 

So now running drums serviced by all-round Goodridge flexibles.

The Eezi-bleed will have to wait for another day before discovering if this duffer could use it properly! 

Best, Colin.

[Colin]

Pete:- thanks. But I'm not quite sure what you are saying there (it's me, not you).

Size 10? I thought my 7/16th was a bit loose on the nipples!

I tend to use a jam jar with fluid in the bottom that the nipple-connected tube sits in. I've not placed this at a level above the brakes though. It's a thought . . . 

Best, C.

[Mark B]

I have always used a smear of red  rubber grease on the cylinder bore behind the seal after assembly. Just press the piston in by hand, grease the bore and on release it lubricates the edge of the seal. I then put a small amount of rubber grease over the washer and circlip before fitting the boot to help prevent moisture entering the cylinder. Wouldn't be surprised if the repro seals were faulty. Just replace the clutch master seals on my Vitesse, probably 8 years old, but only done max 1000 miles, seals felt soft and easily rolled off the piston. 

Currently dismantling 20 odd brake/clutch master cylinders collected over the years to rebuild. Some of the original girling rubber seals still feel like new, and I needed a small screwdriver to peel the seals off. I obviously wouldn't reuse them,  but Just a different quality of rubber material. 

[johny]

48 minutes ago, Colin said:

Folks:- so having re-fitted the internals as I had re-built them, lubed heavily and, out of madness, continuing to pressurise the piston & internals, I found most of the time there was a small delay in the internals & piston returning to resting position in the cylinder after being pushed in. Once in several 'pushes', the internals stayed in - and up - the cylinder. Not happy with this, off to a local mechanic chap I went. He confirmed my reconstruction was all good and the movement of the internals not right. We both concluded the middle seal (8) was just too tight. Fortunately, I had another repair kit and swopped it for the tight unit & ditched the tight unit so I can never use it again. Immediately, there was a movement that allowed an instant return of the internal piston when pressure released. On that basis and that being more normal as I recalled from my previously completely successful work of this ilk, I refitted the M/C and bled the system - successfully. Quite an eye-opener, this, for me. I've never experienced having a duff, overtight seal on these cylinders (identical brake & clutch & brake), knew it wasn't right,  but just needed my hand-held to confirm it was not anything I had done! 

So now running drums serviced by all-round Goodridge flexibles.

The Eezi-bleed will have to wait for another day before discovering if this duffer could use it properly! 

Best, Colin.

Still think the bore cant be uniform size along all its length if the previous seal only stuck in one area but if a smaller seal works its all good👍

[Colin]

Chaps:- 

Before changing seal no. 8, I did ensure the internals were lubed. And as stated, I thought I'd cracked it - except the pistin did not return to resting position immediately and then sometimes not at all. At which point I decided to swop it out.

Johny:- I reckon only Girling can say if the cylinder is in any way tapered!

And yes, all reports say rubber is not what it was (easy, chaps!). I confess the kits I've used are not new, but note the epithet, 'made in India' printed on the label - despite being Girling branded (I think genuinely, not like a hookie omega watches!)

Best, C.

[Mjit]

Just put the Eezibleed on the SoS (Shelf of Shame), in my case next to at least 2 other pointless one-man bleeding tools I've bought over the years and just buy yourself a Vizibleed.  The only one I've found that works each and every time and at under £5 online/only £5.29 from Halfords, and has me wondering why I keep buying 'better' ones (that don't work)!