Has anyone ever opened a mk3 servo?

[brian grech 114]

Hi has anyone ever opened a brake servo to replace the inner parts with new ones. If yes any pics and level of difficulty please.

Thanks

[Danish 294]

 

I seem to remember that there are at least two types - one can be opened (and I think has indentations for a large spanner) and the other is not designed to be opened?

[RT 1006 137]

I seem to remember that there are at least two types - one can be opened (and I think has indentations for a large spanner) and the other is not designed to be opened?

That's how I understand it too. On the earlier ones the body and back plate are a bayonet type fitting and can be separated, though I don't know how easy it is to do, some early Mk3 Haynes manuals have a diagram and procedure for this. The later servos are crimped together and cannot be opened, or at least not easily.

[Tigdlo 27]

I do know that inside is a large spring.

Take care!

[brian grech 114]

Thanks guys/gals mine is an early type servo, unsure what to do,whether to leave it untouched or refurbish it.

[RT 1006 137]

Thanks guys/gals mine is an early type servo, unsure what to do,whether to leave it untouched or refurbish it.

Remove the non return valve and nose seal then you'll be able to get a reasonably good look inside. If it all looks clean and rust free inside then I'd leave it. Sourcing a replacement diaphram and seals etc will probably be quite difficult and if the originals are already in good condition then it's unlikely that new replacements will make much difference anyway.

 

You'll get a fairly good indication of serviceability just by removing the non return valve, placing a vacuum cleaner suction pipe over the hole in the body and and by pushing the servo actuator rod in by hand you'll feel the servo assistance.

 

As for the outside, if it's rusty, which it probably will be, then grit blast it then filler prime then paint. Couple of pics of my refurbished one below.

[brian grech 114]

Remove the non return valve and nose seal then you'll be able to get a reasonably good look inside. If it all looks clean and rust free inside then I'd leave it. Sourcing a replacement diaphram and seals etc will probably be quite difficult and if the originals are already in good condition then it's unlikely that new replacements will make much difference anyway.

 

You'll get a fairly good indication of serviceability just by removing the non return valve, placing a vacuum cleaner suction pipe over the hole in the body and and by pushing the servo actuator rod in by hand you'll feel the servo assistance.

 

As for the outside, if it's rusty, which it probably will be, then grit blast it then filler prime then paint. Couple of pics of my refurbished one below.

Thanks a lot for info, wow what a transformation of the servo, to be honest one of the reasons i was going to pull it apart was to blast it and have it powder coated. Thanks again.

[cortina-city 141]

failure on these is quite rare.

good results can be achieved by carefully blasting, filling and priming

sanding then paint

 

never known one fail but have known them go weak

i had mine on Ruby stripped and rebuilt

i didnt want to attempt seperating it. that spring inside is tricky

 

it aint worth it without special tools

if you want a really good servo have it professionally rebuilt.

 

for brakes i left the servo and master cylinder to a specialist brakes company ,

 

http://www.jlspares.com/

 

these guys are the masters (excuse the pun)

 

then you know it will be right.

 

brakes are too important.

 

for all the time and effort and money you done on that incredible rebuild i would send it to them. (if you feel its faulty)

 

i suppose you could do a leak test on it, if it dont leak its prob ok. why not telephone them and ask for info.

 

they told me it was best to rebuild as the rubber / spring and other parts work better if replaced (i guess they biased though!)

 

I MUST SAY RUBYS BRAKES ARE VERY SHARP FOR JUST STANDARD BRAKES

 

so for me it was worth it.

 

i can tell the difference on the pedal compared to older servos i have

 

heres what they did:

 

stripped and replaced all internal servo components

shot blasted and primed the casing

resleeved the master cylinder with stainless and fitted new seals.

 

for my calipers i chose 'big red'

i then used mintex pads with copperslip on the squal shims

stainless pad rods and fitting kit

 

perfect

 

for rears just standard setup with new rear cylinders and mintex shoes

 

i think the brake rebuild is covered in my online videos

 

good luck brian and superb looking resto, love the primer on the panels

[brian grech 114]

failure on these is quite rare.

good results can be achieved by carefully blasting, filling and priming

sanding then paint

 

never known one fail but have known them go weak

i had mine on Ruby stripped and rebuilt

i didnt want to attempt seperating it. that spring inside is tricky

 

it aint worth it without special tools

if you want a really good servo have it professionally rebuilt.

 

for brakes i left the servo and master cylinder to a specialist brakes company ,

 

http://www.jlspares.com/

 

these guys are the masters (excuse the pun)

 

then you know it will be right.

 

brakes are too important.

 

for all the time and effort and money you done on that incredible rebuild i would send it to them. (if you feel its faulty)

 

i suppose you could do a leak test on it, if it dont leak its prob ok. why not telephone them and ask for info.

 

they told me it was best to rebuild as the rubber / spring and other parts work better if replaced (i guess they biased though!)

 

I MUST SAY RUBYS BRAKES ARE VERY SHARP FOR JUST STANDARD BRAKES

 

so for me it was worth it.

 

i can tell the difference on the pedal compared to older servos i have

 

heres what they did:

 

stripped and replaced all internal servo components

shot blasted and primed the casing

resleeved the master cylinder with stainless and fitted new seals.

 

for my calipers i chose 'big red'

i then used mintex pads with copperslip on the squal shims

stainless pad rods and fitting kit

 

perfect

 

for rears just standard setup with new rear cylinders and mintex shoes

 

i think the brake rebuild is covered in my online videos

 

good luck brian and superb looking resto, love the primer on the panels

Hi Pete wow a very detailed response. i have two servos and one still looks very good when the piston is pushed (still have to do the vacuum test but otherwise looks to do what it should do).

Thanks for the compliment the aim is to have it in colour in a couple of months time, i'm going to bring it down on its axle and subframe, check thateverythings is ok and paint.

Hopefully will be done by December.

Thanks again Pete

Edited May 21, 2018 by brian grech

[cortina-city 141]

im still posting vids on youtube, may do a build thread on here on bramble, but im spending most my time on my own forums now. i have set up a patreon site which helps. ill pop in every now and again on here. pete