Bleeding new brake system

Maintenance advice to keep your Spider in shape.
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BigMacDave
Posts: 50
Joined: Wed Sep 14, 2016 2:41 pm
Your car is a: 1978 124 Spider
Location: San Antonio, Texas

Bleeding new brake system

Post by BigMacDave »

Hello,

In the process of replacing the whole brake system, MC, calipers, compensator, lines.. etc

Should finish this weekend

I can not find anywhere that talks about the order of the bleeding. Of course I will bench bleed the MC, but beyond that, is there a certain order to the corners. Also, what about the compensator. Any special attention or method?

Thank you

David
DieselSpider
Posts: 2130
Joined: Wed Dec 24, 2014 10:21 pm
Your car is a: 1978 124 Spider with Isuzu Turbo Diesel

Re: Bleeding new brake system

Post by DieselSpider »

SOP for almost 100 years is to start with the wheel furthest from the master cylinder and work your way to the front. RR, LR, RF and LF if you have a left side driving position. All the compensator requires is that the rear axle is supported to keep the compensator open. If you leave it hanging then the compensator will be closed and the rear brakes will not bleed.
BigMacDave
Posts: 50
Joined: Wed Sep 14, 2016 2:41 pm
Your car is a: 1978 124 Spider
Location: San Antonio, Texas

Re: Bleeding new brake system

Post by BigMacDave »

Ok thank you. I guess I should have assumed if it didn't say otherwise, SOP.

Right now the rear of the car is supported by jack stands on each side of the axel. Would that be considered in the open position? I'm still not quite sure how that compensator works.

Thank you
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lglade
Patron 2018
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Posts: 327
Joined: Sat Dec 07, 2013 7:05 am
Your car is a: 1984 Pininfarina
Location: Mukilteo, WA

Re: Bleeding new brake system

Post by lglade »

Yes, if the rear of the car is supported by jack stands under the axle, then you're ready to bleed the rear brakes. On the other hand, if the car was supported by the body with the axle unsupported (e.g. with wheels off the ground like you might do when you're changing shocks), then the compensator would prevent the flow of brake fluid to the calipers.
Lloyd Glade- Mukilteo, WA
1984 Pininfarina Spider Azzurra
1962 Fiat 500D - wife's car
2015 Subaru Outback
2017 Ford Focus RS
DieselSpider
Posts: 2130
Joined: Wed Dec 24, 2014 10:21 pm
Your car is a: 1978 124 Spider with Isuzu Turbo Diesel

Re: Bleeding new brake system

Post by DieselSpider »

The compensator works by sensing the distance between the rear axle and the frame of the car to determine how much load is on the rear axle so it can regulate pressure to the rear brake calipers and prevent loss of control due to a full rear wheel lockup. It is basically a self adjusting pressure regulator that cuts just about all flow of brake fluid to the rear wheels when they are off the ground.
BigMacDave
Posts: 50
Joined: Wed Sep 14, 2016 2:41 pm
Your car is a: 1978 124 Spider
Location: San Antonio, Texas

Re: Bleeding new brake system

Post by BigMacDave »

thank you very much for all of the replies.

Right now the car is totally off the ground, wheels off. the front is supported by floor jacks at the body lift points back about 6 inches or so for the wheel wells, and the back is supported by floor jacks on the axel as far out to each side as i could put them without interfering with taking brake hardware off.

i think i understand this is ideal to bleed the back and the compensator.

i have not put the new compensator on yet, with it lifted like it is, does that put tension on it and make it hard to take out/ reinstall?

I will be using pressurized pneumatic bleeder set at around 15 lbs of pressure when its time to flush all the air out.
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