Brake servo rebuild

[Mark Goldsmith]

Im looking to take my brake servo apart, the servo has sat around for a good while and looking at the state of the master cylinder it looks like it’s leaked into the servo. Have order a rebuild kit to rebuild. I’m currently  stuck on how you take it apart. Does it twist and turn or do I have to hammer the lugs apart? Have uploaded a picture. Any help would be appreciated.
Cheers
Mark

[Jaydub]

Hi Mark,
It twists until the cut outs align with the lugs. BUT it will be corroded and stuck on the rubber diaphragm! I made up a strip of metal with suitably drilled holes to bolt onto the studs to gain some leverage. You need to hold it very securely in a decent vice AND put a ratchet strap or similar around it because there is a very strong spring inside. Be Careful!!
Good Luck.

[Dave Gee]

 

 When you get the servo apart, there is a push rod inside with a nut on one end. Measure the distance from the end of the rod to the nut so you know the point at which to put it back when you reconstruct the servo. I would also recommend getting the body of the servo plated at the same time as this will remove rust both inside and outside, and ultimately help to extend its life.

Dave Gee

[Jay]

Having taken a couple apart recently, here’s my advice. In a big vice go around the circumference squeezing the two halves together so you can see a small amount of movement, as this frees them up. Then clamp the circumference of the front part (master cylinder side) in a vice, don’t clamp the bolts, as they will bend and distort the body. Then I bolted a 4ft piece of heavy duty dexion (the holes line up) to 2 of the 4 bolts, bolt them down hard otherwise the bolts will bend the body and become loose. Then push with all your weight, and or hit it with a mallet, it takes some moving. Once it starts it becomes a lot easier, and as Jaydub says be careful for the last few mms as the spring pushes the halves apart.  The other challenge is stripping the internals as you have to push a square circlip type clip through a slot in the plastic body to disengage the pieces. Lastly don’t remove the piston seal as it’s impossible to put back, as you have to stretch it a lot to get it back on.