Wheel Cylinder -Replace or Repair

[Stratton Jimmer]

The nearside rear brake cylinder on the early Mk3 GT6 has blown and leaked Dot5 inside the drum. Given that it is probably 52 years old, should I replace it or repair it? Should I do the pair at the same time? I'm not even sure if replacement seals are available these days. Any advice would be welcome. Thanks.

[Unkel Kunkel]

Depends on what the piston and the bore are like.

If there is doubt about the surfaces being corroded :replace.

Certainly do as a pair.

Depending on history, maybe a time to  review other parts of the hydraulic system.

 

 

[Stratton Jimmer]

A quick scan shows that Rimmer, Canley and Paddock all have seal kits. New cylinders are not overly expensive so I think I will change the pair of wheel cylinders. Are new fitting kits recommended or will the old suffice? Would this be "spoiling the ship for a ha'porth of tar"?

[dougbgt6]

Early wheel cylinders are surprisingly cheap on Rimmers, around £12. Repair kits £7. I'd just replace both cylinders Late cylinders are however hen's teeth, I got 2 spare in the drawer! 

Doug

[dougbgt6]

What is the fitting kit?!!

Doug

[Stratton Jimmer]

The fitting kit is the spring clips and the like. It is listed on Paddock's site. My six is an early Mk3 KE3529-O so everyone stocks the cylinders. I'm taking in the Stoneleigh show in a couple of weeks time so may just have a look at what might be available there and if nothing, order them afterwards. There's no rush as the weather isn't exactly conducive to doing such a job out on the drive. I don't have a garage as such but do have a car port. Meanwhile I can use the Sixfire!

[Chris A]

As it happens my 13/60 is 'up the road' with the local garage having rear brakes checked out - drivers side has started to stick from time to time. I'm waiting for him to get back to me but I have checked out French suppliers ready for any parts needed. Should it be the cylinder I will replace both sides with new plus if the mechanic has any doubt the fixing kits and anything else that might be on its way out. I don't know when/if these parts were changed.

The parts are quite cheap and as it is the brakes, which apparently are quite important 🙄, I will stump up 😉

[Pete Lewis]

by fitting kit do you mean the two horsehoe clips  

if they are the black finished tempered sprung its often the old  are fine after a clean up

any aftermarket shiny ones generally dont interlock and are rubish 

you must check for back plate grooving at the HB pivot  

fit the clips flat one against the backplate the curved on to lock over the top of the fat one 

disconnect the HB cable  fully lock the shoes up  then refit the cable to a nice fit no tension

de adjust about oneturn 4 clicks 

Pete

[Stratton Jimmer]

Thanks Pete, that tells me an awful lot more that the Haynes manual. I have decided that I might as well do both sides with new cylinders, pistons and seals. Also included will be the dust covers. I shall follow Pete's advice about the spring clips too. Thanks everyone for your advice.

[Clive]

16 hours ago, Chris A said:

As it happens my 13/60 is 'up the road' with the local garage having rear brakes checked out - drivers side has started to stick from time to time. I'm waiting for him to get back to me but I have checked out French suppliers ready for any parts needed. Should it be the cylinder I will replace both sides with new plus if the mechanic has any doubt the fixing kits and anything else that might be on its way out. I don't know when/if these parts were changed.

The parts are quite cheap and as it is the brakes, which apparently are quite important 🙄, I will stump up 😉

Avoid new springs for retaining the brake shoes, the little ones with the caps. New ones are more suited to a biro or suchlike, really weak. The old ones are always fine, if grubby. 

The main issues seem to be wear or corrosion of the backplates, easily rectified with some emery/a file and rarely a bit of weld. 

New cylinders are a good idea, as is using some copper grease to allow all to move sweetly. I usually take the adjuster apart, clean up and regrease, makes life easier and means they won't seize next time you have to adjust them. 

[Chris A]

1 hour ago, clive said:

as is using some copper grease to allow all to move sweetly

I put a tube of copper grease in the boot along with imperial sockets & spanners ( don't forget here it is mainly metric). I forgot to tell the mechanic there was the grease, memory failure again.

[Pete Lewis]

and do make sure the trailing shoe has the unused rectangular hand brake lever hole is at the bottom 

many get the trailing shoe upside down and that makes brake performance and HB less than good 

Pete

[DanMi]

You will probably want a new set of shoes as well as the old ones will be contaminated with brake fluid

[dougbgt6]

I remember my dad setting fire to contaminated brake shoes! Off the car obv. Works well. brake fluid burns easily. 

Doug

[PeteH]

27 minutes ago, dougbgt6 said:

I remember my dad setting fire to contaminated brake shoes! Off the car obv. Works well. brake fluid burns easily. 

Doug

More of the "stuff we did". Much of which would get the "Elf & safety" Police wanting to "flog" and clap you in irons to-day. Nowt wrong with that, they where all asbestos back in the day anyway!. "We" burned old engine oil back then too, one way to keep garage warm!. I understand that`s a "flogging" offence now?

Pete

[dougbgt6]

23 minutes ago, PeteH said:

"We" burned old engine oil back then too,

I take mine to the dump where they have a giant vat. I wonder what becomes of it? 

I remember as an apprentice being told to pour mercury from broken glass switches down the sink.

Doug

[Chris A]

3 minutes ago, dougbgt6 said:

I take mine to the dump where they have a giant vat. I wonder what becomes of it? 

When nobody is looking they use it to heat their 'office' 😱

[DVD3500]

Slightly off topic: Has there been any proof that the 1" rear cylinders were simply a case of rationalization and not an attempt to improve rear braking on 1500s?

I am rebuilding my Spitfire using parts from MKIVs and 1500s and was going to use the longer 1500 drive shafts and cylinders in the rear and was always wondering about those changes...

 

[trigolf]

1 hour ago, Chris A said:

I take mine to the dump where they have a giant vat. I wonder what becomes of it? 

It goes in a centrifuge and then the filtered remains turn up as bargain engine oil in your local cheapo shop - possibly????!😄

 

[Colin Lindsay]

7 minutes ago, trigolf said:

It goes in a centrifuge and then the filtered remains turn up as bargain engine oil in your local cheapo shop - possibly????!😄

 

It's certainly recycled; there's a place near me that collects it. No idea what it ends up as, though.

 

[JohnD]

Centrifuging is too energy intensive!   Oil re-refining companies -and there are a dozen or more in the UK - will separate the heavier contaminants in a settling tank, that allows water to float to the top too.  Then  it's refined, like crude oil.

John

[Josef]

Oh that’s interesting John. Coming from a background in chemistry I assumed the engine oil was treated like our non halogenated waste which was burned and the fumes scrubbed. Re refining is much more sensible!

[PeteH]

Small matter of accuracy. No Lubricating oil`s have a specific gravity above 1 (Water) more usually around 0.8sg, in fact the only generally available oils to so do are the really heavy grades of Bunker C (sg max 1.005), There are some very specialised "oils" with sg`s above 1.0, in very small and expensive quantities. The sort of Heavy oils we burned in boilers and Marine Engines, Still did when I quit around 1980. Much of which is now only used in the sort of very old vessels coming to the end of their comercial lives.

Centrifuging Lubricating oils used in marine engines is still commonplace, And All Heavy fuel oil was centrifuged before being heated to 80C and above for use in the main and auxiliary Engines. In recent times there has ben a massive reduction in the use of HFO, due to pressure from enviromental sources. The huge land and Marine boilers which fired with HFO`s are mostly now phased out, as with Coal, except for the like of China, India, and Russia, and other "usual suspects". Those remaining in "westernised" countries are being converted to use Bio fuels/Biomass. Some of the huge LNG ships actually burn the "boil off", about 1/2%/day from the cargoe as a means of keeping it liquified in transportation.

Pete

[Clive]

7 hours ago, PeteH said:

"We" burned old engine oil back then too, one way to keep garage warm!. I understand that`s a "flogging" offence now?

I am planning on making a waste oil fired heater. Still looking for some 4" steel pipe for teh flue as I have no wish to spend £80 on teh 3m length I need. Apart fron tham, a calor gas bottle and some odds and ends. 

Commercial garages CAN buy a licence, but I think about 2k a year per heater! Otgherwise they pay for it to be collected, then transported to Drax and burnt to make electricity to power the garage electric heaters....

I plan on cutting out the middleman.

[Peter Truman]

8 hours ago, PeteH said:

"We" burned old engine oil back then too, one way to keep garage warm!. I understand that`s a "flogging" offence now?

When I was at college mid 60's I used to service and maintain my Sprite Mk1 at a local garage (stables from an old big house) who put saw dust on his earthen floor from a local carpenter's works to catch oil spills etc as it got dirty he mixed the sawdust with old engine oil and burned it in a stove/burner to heat the stables, worked well. As said nowadays a whipping offence, they were different times!!