bleeding brakes!!!!

[jord294]

hi guys

i have been doing part restoration on my '91 405 mi16 2wd and have a problem

before stripping the car down it drove perfectly, and brakes were spot on.

i have replaced [u]all[/u] brakelines, calipers and fitted a new load valve to rear axle

after a while i seemed to have bled all air out of the system. pedal has excellent pressure

but when i start the car, the pedal goes soft, but not straight to the floor.

do you think i still have air in the system?

thanks

[SpaceGhost]

Sounds normal, it's just your servo kicking in but if you're in any doubt, would do no harm to rebleed.

[jord294]

thanks

i used a one man bleeder, but think i'll invest in a pressure bleeder.

also found out that i need to position the rear caliper so the nipple points upwards, to expel all air.

[The Wookie]

That sounds normal for a Servo assisted car.

Basically the pedal should settle a bit lower and remain steady. If it carries on creeping until it hits the floor then there's fluid either leaking out or getting past the master cylinder seals.

Having said that in my experience some high servo applications (powerful 4x4's and luxury saloons for example) do creep very slightly when in good condition.

[nsa]

My car has a similar issue. It's a track beast and the brake pedal when pressed is a little too low for heel/toe. Is there anything I can do to make it firmer? The brakes stop the car fine and the pedal doesn't creep to the floor when pressed.

[Locknut]

jord294 said:

also found out that i need to position the rear caliper so the nipple points upwards, to expel all air.

I don't understand this. The bleed nipple should always be at the top. Have you accidently swapped the callipers left/right? Swapping would cause the nipples to be turned down. You will never bleed the callipers properly unless the nipples are at the top.

[jord294]

Locknut said:

I don't understand this. The bleed nipple should always be at the top. Have you accidently swapped the callipers left/right? Swapping would cause the nipples to be turned down. You will never bleed the callipers properly unless the nipples are at the top.

no, i haven't accidently swapped the calipers. the bleed nipple is at the top on the side



but according to the haynes manual and advice from a peugeot forum, when replacing rear calipers, the caliper must be bled with nipple pointing up and a piece of would wedged so piston doesn't pop out.

will give it a go over the weekend, and update

[SpaceGhost]

Provided the caliper is properly mounted with a disc and pads fitted, the piston will never pop out in a million years.

[Locknut]

I can't make out the nipple but I think I know what you mean. I don't think you need to remove it to bleed, just take out the bottom bolt and rotate it about the top bolt by about 15deg. That way the pistons and pads will still be in contact with the disc and you will not need a block of wood. Let us know how you get on.

[Old Merc]

I often had problems bleeding the rear calipers on 405`s.I would unbolt the caliper,balance it on top of the disc with the nipple up,move the piston back with a wind-back tool and then bleed it keeping the wind-back tool in place.

[jord294]

Old Merc said:

I often had problems bleeding the rear calipers on 405`s.I would unbolt the caliper,balance it on top of the disc with the nipple up,move the piston back with a wind-back tool and then bleed it keeping the wind-back tool in place.

that's how i'll be doing it.

that'll teach me for fitting shiny new parts to another peugeot. said i wouldn't do another resto after doing my 309 gti

[Old Merc]

Now that photo brings back memories.I had a Mi16X4 (pre Kat) in the early 90`s (when I was a boy racer)I had it professionally re-chipped,the induction altered,Speedlines with 205 Yoco`s.It would do 150mph and stick to the road like glue! I think they were one of the most underrated cars of the time.

[jord294]

this is the alloy block, and sounds sweet as

i also have a set of 405 T16 alloys that will go on the car after winter.

got a gunson pressure type brake bleeder now, so will let you know how i get on

[jord294]

Old Merc said:

I often had problems bleeding the rear calipers on 405`s.I would unbolt the caliper,balance it on top of the disc with the nipple up,move the piston back with a wind-back tool and then bleed it keeping the wind-back tool in place.

this is how i did it, but sadly i still have a bit of pedal travel when the car is running it doesn't go to the floor and the car brakes evenly

i have a super solid pedal when car is switched off though

i was told that maybe there could still be air in the system, but can't seem to get anymore out. even with car running and not

perhaps my abs pump is worn?? i have a spare one i could try. i also have a spare new m/c

is it possible air could be trapped via the brake pressure regulator?

should i try a pressure bleeder?

it's the only issue i have now, as it would of passed it's m.o.t yesterday if pedal had of been stiffer

[Nick1point9]

Sounds exactly spot on for servo assisted brakes, firm when off, slight travel but no creep when running.

[Dave Brand]

jord294 said:

should i try a pressure bleeder?

I rebuilt the rear calipers on my 405 SRi a couple of times. Never had any problems bleeding the system using a Gunson's Eezibleed.

If I remember correctly it was necessary to jack up under the suspension arm on the side being bled to ensure that the pressure relief valve wasn't affecting the flow of fluid - that may, however, have been another car I'm confusing it with!

Lovely car, by the way!

[Fraser65]

Try bleeding it with the ignition on (engine off) so the abs pump can run.

[Nick1point9]

jord294 said:

it's the only issue i have now, as it would of passed it's m.o.t yesterday if pedal had of been stiffer

I missed this last time - what was the exact failure (as written on the refusal).

[Old Merc]

How many miles has it done since replacing everything?? Give it a good "left foot on the brake" test run to bed in the pads and discs.

[jord294]

small update

have since learnt that the abs pump on the car wasn't working.

i have replaced the unit, and now i can hear the pump when i switch the ignition on

will be back to report when i bleed the system again