I recently completed a renovation of my brake calipers on my 1983 308 GTS Quattrovalvole. The rear calipers on a 308 need to be manually adjusted for best performance. The 308 has the same Ate rear brake calipers as a Porsche 914-6. Eric Shea of PMB Calipers Inc has posted a detailed description on how to do this adjustment: 914 Rear Caliper Adjustment Procedure He has also posted on FChat the procedure for rebuilding 308 brakes: 308 Rear Caliper Rebuild Thread It is interesting that Eric says that the mechanical handbrake system on a 914-6 works quite well. It does not on a 308. This makes me think that the difference is the different cabling systems on the two cars. For the Porsche, the cable splits almost immediately after the handbrake lever and pulls directly on each of the levers. On the 308, a single cable routes through a long metal tube before cable tension is split by a cable-tension pulley system at the rear of the car. If what Eric says is true, it then seems to me that the problem is friction in the tube not so much the mechanical brake lever system. I wonder how we can fix that. My first thought is a Teflon liner in the metal tube. By way of background, my driver-side rear caliper had begun leaking brake fluid from the parking brake area. I sent all four of my calipers to PMB Calipers Inc in Sandy, Utah. I am very pleased with the results. I also bought Porterfield pads through PMB.
In my opinion, the problem lies with the inherent variable tension in the cable/reel system; there are too many places for the cable to *not* be tight. Motion of the brake lever itself seems to be enough to overcome any potential friction issues in the tube.
Or, when forgotten in gear the pads are worn to the point of gone...I rarely use mine as they can also "frezze on" and then you have the same situation, dragging overheating.... Probably greasing everything top to bottom and your plastic tube liner has merit in my mind. The enemy is rust.....
Another item to check, make sure and adjust the brake pads for .002 clearance on the caliper. This requires occasional readjustment. Check that the brake lever doesn’t go all the way to the top notch to fully engage My E brake does hold the car on an incline, but I would want to rely on using to stop the car at any speed.
Another flaw of the handbrake design on the 308 is the location of the lever. It simply sits too high on the center console for applying appropriate force even for the taller drivers. Except body builders and wrestlers. On the Porsche 914 it's located between door sill and seat deep down on the floor. I also think, that Ferrari addressed this issue when they relocated the handbrake lever on the 328 where it's located like on the P 914. Best from Germany Martin
That's a completely different design. Not only the relocated handbrake lever, but more efficiently, integrated drums for the handbrake inside the brake discs, as opposed to the handbrake acting on the disc pads on the 308. Best from Germany Martin
Image Unavailable, Please Login The E brake on my 82 308 was engaging a bit high, indicator of adjustment needed. So I adjusted the rear brakes today… You can get to the outside adjustment without removing the wheel. The E break engagement is a bit lower now.
Pad. No "s". The hand brake moves the inner pad against the rotor, it doesn't squeeze the rotor. Well, "pads" in that there is one pad on each side of the car. I've mulled over lengthening the arm on the pulley thing where the cable attaches. It would give the handbrake handle move travel, but more leverage.
Brian, I have considered that option as well. I think it would increase the torque on the pad and increase the effectiveness of the rear brake.
FWIW when ever the e-brake handle get to ‘high’ and doesn’t hold well.... I adjust the brake pad clearance and the e-brake is okay. Even on a hill..... until more brake wear. Just saying....
I used to have a GT4. I adjusted the parking brake per the accepted instructions and it held very well. I thought you all on Fchat were incompetent for having your parking brakes not work. I sold that car and bought a QV. The braking system components are exactly the same on the two cars. I can't get the parking brake to hold the car worth a crap on the QV.
