912 brake overhaul.

Tedri Mark · Post by **Tedri Mark** » Sat Jan 17, 2004 4:29 pm

Following instructions on pelican parts. com, I've got one of the caliper's off, removed pads etc, reconnected it to brake line to push the cylinder out but it wont budge. Pushing on the brake pedal is very hard, but it does move, but i don't think it is pushing the cylinder out. Any ideas?

Post by **Miggs** » Sat Jan 17, 2004 4:51 pm

spooky been doing mine today aswell but mine were seized coz its been sitting for twenty years

i did the same took the shoes out and pump the brake pedal it does take a while to get them to go but they will go trust me once you get them as far as they go you will need a air line to pop them right out

Once out emery paper 400 the piston and the barrel fit the new seals put plenty of rubber grease in and hey presto

if you are still stuck drop me a pm or email

mike

912uk · Post by **912uk** » Sat Jan 17, 2004 8:10 pm

OK I might be able to help here cos mine were seized in solid big time. No amount of air would get them out. So don't panic.

IF air will not get them out this will work. One while you sort all the bits out you need get a tub of Desiel and put them in there and leave them.

You need to get to borrow a 10ton body ram. If you don't know what one of these looks like have a look on Machine mart. on line.

I have a tool for this that some one still has ( I know who )... this is a treaded bolt that fits the Porsche calipers the other end has a thread to be the same as the 10ton ram thread. On the ram the head has to be taken off to return it back to a Standard BSP. thread. I also have a T peice in the middle to let off any excess pressure when it biulds up......

Any way you need to make a tool like this. and borrow a 10ton body ram. Mean while the calipers in the deisel will now be nice and soaked and this will really help ease them out.

NOTE kiddies please get the supervision of both set of parents when doing this.....

The ram will push out your piston at a fair rate of knotts so fingers well out of the way and it's best to put abit of wood in the way to take the force. You will need once one is removed to clean the area and put it back in the caliper and get a G clamp to hold it in place while you do the whole thing all over again to the other one. Then air will get them both out.

Took me a liitle while to sort them but I have since done another set for a 912 owner with my TOOL and I did all 4 calipers in 30mins. Arr and that bottle of wine for it was very nice hmmm SUMMER those were the days...

any probs mail me.

pix912 · Post by **pix912** » Sun Jan 18, 2004 5:47 pm

I've rebuild all 4 calipers of my 912 last year after a very, very scary experience. I was doing a 120 km/h on the highway, on a beautiful day in May, targa top in the trunk, rear window down, pure fun. All of a sudden my left rear brake got stuck, first I felt the car slowing down, then a big bang, luckily I was on the slow lane and manged to stop the car on the emergency lane. When I got out there was a lot of smoke coming from the left rear wheel and FIRE! Luckily (again, the Porsche Gods were with me that day, or not?) I had a brand new fire extinguisher in the car and managed to kill the fire before it could do any damage to the car. It took me 4 or 5 tries, the caliper was so hot that the (small) flame kept coming back. After 45 minutes of letting everything cool down I was able to remove one cylinder and pad, united forever (see picture).
What caused this? You probably know, the car still had the original rubber brake lines from 1968, they looked pretty good on the outside but over time the inner canal got narrower and narrower. The canal was still wide enough to let the brake fluid pass when the brake pedal was pressed, but not all the fluid returned so more and more pressure was built up.
Some good advice, while you're doing your caliper(s), replace all the rubber brake lines, they are cheap and this can save you a lot of trouble, I know!

Back to the the stuck caliper. On my car 4 were stuck and I've got them out without any special tools. Remove the complete caliper and put it in the freezer for one night. Next day heat up the outside of the caliper and hit it with a wooden hammer, the cylinder will fall out after a few knocks.

Good luck,

Piet (from Belgium)
912 SW Targa (1968)

Post by **Miggs** » Sun Jan 18, 2004 6:43 pm

u were lucky that day

like you said it is worth changing everything if you are doing it

912uk · Post by **912uk** » Sun Jan 18, 2004 7:17 pm

Hi'a I remember that we were talking about meeting up for 356 international last year nice to see you over here on the web site mate. Glad you got it all sorted . So you coming over to some of our do's in the UK (with no brake probs this time )

Mark

Tedri Mark · Post by **Tedri Mark** » Tue Jan 20, 2004 1:48 am

PLOP!

Managed to get one piston out of a caliper, so i'll clamp that in and try the other - fingers crossed!

pix912 · Post by **pix912** » Tue Jan 20, 2004 9:43 pm

Hi Mark,

I didn't know you were the one I emailed last year. The story above just happend the day before 356 International, so there's no way I could have made it.
Didn't know you had that many 912's, when do you find the time to drive them ?
I sure will try to come over to one of the events this year. Any suggestions on which event is the most interesting (and close to Dover) ?

Piet

912uk · Post by **912uk** » Tue Jan 20, 2004 10:15 pm

pix912 Hi'a I thought it was you... just a few cars

Tedri Mark how are you getting on with the brakes now. With the right tools it takes just a few mins

Tedri Mark · Post by **Tedri Mark** » Sat Jan 31, 2004 3:37 pm

still just the one out - only have saturday's to work on my cars and i work till 3 am friday and from 6pm saturday so i don't have much spare time to do much. Gonna pop out the other piston on that one caliper then that's one done - it'll only take 8 weeks to get them all out! :D

912uk · Post by **912uk** » Sat Jan 31, 2004 6:12 pm

told you. When I did it 1st time around it took almost that long but since I have had the tool and the press 1-2 hrs for really seized ones.

Mark