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(Post Link) post #1 of 9 Old 05-08-16 Thread Starter
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front inboard brakes

Hi all

I have rebuilt my front inboard brakes but as my car is non standard, I am not sure if the way the pipes run is correct, can someone lift their bonnet and check for me.. I have 3 outputs on the master cylinder but 1 has a bleed nipple in, and I'm not sure if the front and rear lines are in the correct holes or even if it matters? The brakes are still not brilliant after re-build so just need to make sure the setup is as it should be..

Please see crude drawing of setup with t-piece in front brakes..

Thanks

Simon
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Your drawing is different to standard. Do you still have the pipes that join the front calipers? Through the hole in the gearbox bell housing? The standard circuit split is, from memory: 1 circuit is front and back, the other is front only. I can double check the exact setup on my sud this weekend if you like.
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(Post Link) post #3 of 9 Old 07-08-16 Thread Starter
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Originally Posted by sprint_veloce View Post
Your drawing is different to standard. Do you still have the pipes that join the front calipers? Through the hole in the gearbox bell housing? The standard circuit split is, from memory: 1 circuit is front and back, the other is front only. I can double check the exact setup on my sud this weekend if you like.
If you could, My pipes go through the firewall onto some aluminum brackets I have made where they join the flex pipes shown in the photo. Do you have 3 pipes coming out of your master cylinder or 2? as there is 3 holes cut 1 of mine had a bleed nipple in which I have put back after I rebuilt and painted it.

I found a diagram that seems to show the pipe looping in and out? I cant really tell, it does seem to show 3 pipes coming out of the master cylinder though..

Thanks

Simon
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Yes there are 3 pipes coming from the master cylinder. 2 outlets come out the side of the m/c (one half way along, and one at the front)and one out of the underside at the front.

The rearmost pipe out the side of the m/c comes directly forward, through the bulkhead, and down to the right front caliper. The front pipe out the side goes across the bulkhead and then through a big grommet on the lh side. It then goes down to the left front caliper. The 3rd pipe which comes out of the underside at the front follows the other pipe across the bulkhead and through the same grommet. It then goes to the rear brake compensator and on to the calipers.
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(Post Link) post #5 of 9 Old 09-08-16 Thread Starter
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Originally Posted by sprint_veloce View Post
Yes there are 3 pipes coming from the master cylinder. 2 outlets come out the side of the m/c (one half way along, and one at the front)and one out of the underside at the front.

The rearmost pipe out the side of the m/c comes directly forward, through the bulkhead, and down to the right front caliper. The front pipe out the side goes across the bulkhead and then through a big grommet on the lh side. It then goes down to the left front caliper. The 3rd pipe which comes out of the underside at the front follows the other pipe across the bulkhead and through the same grommet. It then goes to the rear brake compensator and on to the calipers.
Brilliant, thanks for that, My master cylinder has 2 holes at the back and 1 at the front, I am not sure if there is a difference in pressure between individual outlets? at least I know now that I have to re-pipe it.. if "re-pipe" is an actual word,,,

I would imagine that I am not getting adequate amounts of fluid movement with my current setup as it must be half of what it should be with the splitter.

Simon
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I'm no expert, but what you have shouldn't effect the power or effectiveness of the brakes so long as you have the cross pipes connecting the front calipers, and a working rear brake compensator.

I'm pretty sure without the cross pipes you will only have one piston on each front caliper working, which will be very poor.

The main problem with your setup, assuming the cross pipes are there, is that you only have one front brake circuit, so if you burst a front flexi (or some other sudden leak in the front circuit) you will struggle to stop.
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(Post Link) post #7 of 9 Old 10-08-16 Thread Starter
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Quote:
Originally Posted by sprint_veloce View Post
I'm no expert, but what you have shouldn't effect the power or effectiveness of the brakes so long as you have the cross pipes connecting the front calipers, and a working rear brake compensator.

I'm pretty sure without the cross pipes you will only have one piston on each front caliper working, which will be very poor.

The main problem with your setup, assuming the cross pipes are there, is that you only have one front brake circuit, so if you burst a front flexi (or some other sudden leak in the front circuit) you will struggle to stop.
I would have thought though its like splitting a water pipe, 1 bar pressure 1 inch round pipe with splitter into 2x 1 inch water pipes it cant remain 1 bar pressure at the end of both pipes? you are physically spilling the water and the source remains 1 inch so no more water can flow, you end up with half the water coming from each pipe.

You may be correct it may just be a safety thing, I will change it though to make it correct and see if it makes any difference. I have new discs and pads so it may take a run out to bed them in.. It does stop and I cant really compare it to my modern car but I would expect to be able to lock the front brakes, and it just seems dull..

I'm off to the beach for a week or so, will sort it out when I come back then post my findings..

Thanks

Simon
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I don't think the pressure in the pipes has any bearing on how the brakes work, only the pressure in the master cylinder and the brake caliper pistons matters. The pipes are just transferring the fluid.

Working correctly, Alfasud brakes are very effective, and combined with low weight compared to modern cars, will easily match most cars. But pedal pressure is quite a lot higher so they do feel different to new cars.
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As I see it the current setup should work, both calipers have a short line to connect inner and outer halves. However this doesn't make use of the clever safety setup as intended, a circuit split were if one circuit fails you should still have both front calipers working.
Use all 3 outputs on the master, I think you may have a 33 master fitted but this doesn't matter. The 2 holes at the back, use one for the rear line, use the other to go to a front caliper. Use the front hole for the other front caliper. Through the flex-line the pressure goes to the outer halve of the caliper. Then use the outlet on the outer halve to go to the inlet on the inner halve of the other caliper (line through the hole in the gearbox casing). And vice versa. Because of the adjustable and locked in position pistons in our front brakes, if one circuit fails, still one halve of each front caliper is operated and pushes the disc to the fixed not working other halve. Hope I made it clear :-)
Edit: found a pic in my archives to clarify :-) :-)
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'08 GT 3.2, Sud '82 QO, '76 Ti, '75 L, Montecarlo, 308.

Last edited by bert308; 18-08-16 at 21:54.
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