Need help. Audi 90 b3

xxErix · 21-01-22, 07:55 AM

Hello..

I am a little bit mechanically minded but not massively. But i I want to learn

I will be attemting to change clutch master cylinder, bleed breaks, and change oil prrssure sensor.

Can anyone give some tips or something? So i dont **** things up.

Also, is oil pressure sensor just sort of a swap thing or I need to drain oil too.

Thanks

Isimmo · 21-01-22, 08:49 AM

Get a decent one person brake bleed kit if you haven’t done so already.

Remove the drivers seat when doing the clutch master cylinder. Seems excessive in the beginning but you’ll thank yourself later. (Assuming B3 clutch master cylinder is up with the pedal box).

xxErix · 21-01-22, 09:58 AM

Ive got a mate to help me out, so got two people for bleeding breaks

xxErix · 21-01-22, 10:05 AM

Also. Appart from break oil, do i need anything else to bleed them?

mikes2 · 21-01-22, 10:17 AM

In at the deep end there.

Not a lot of room to get at the oil pressure sender. There's 2 of them. Lower one is fairly easy and just needs a spanner. Easiest to go in from the engine mount side. The top one, there is a water hose that gets in the way. I use a spanner behind the water hose which you'll need to stretch slightly away from the block and slot it down behind the sensor (17mm) to undo it. You might lose a small amount of oil.

I'd recommend a pressure bleeder for doing the brakes and clutch. Bleeding is done in order - longest brake line away from the master cylinder gets done first. Rear left, rear right, left front and right front. Minimum of 250ml of fresh fluid from each caliper. I always do more from the first one.

Clutch master is a messy job. Put cloth or towel down in the foot well. Clamp off the hose from the brake fluid reservoir to the clutch. Undo the hydraulic line in the engine bay - you'll need a container to catch the fluid. Note this is an unusual size at 12mm. Inside the car, the hose needs to be pulled off the MC - there's a hose outlet on the top. Based on my experience the fluid will go everywhere. It's held on by 2 bolts which need an allen key to undo.

The most difficult part will be re-threading the hydraulic line into the master cylinder. I'd suggest wire brushing the threads of the line to clean them up. It needs to be bolted up inside the car first. You'll then need to bleed the clutch from the slave which is on the gearbox. Turn the steering all the way to the right for better access

xxErix · 21-01-22, 11:20 AM

Thank you. Very useful stuff there. Hopefully me and my mate can figure it out. Ive orded all new parts from autodock. So hopefully will all fit.

21-01-22, 08:49 AM	#2
Isimmo Super Moderator Classic Audi Club Member Join Date: Jul 2007 Location: Sissix-by-the-sea Posts: 15,218	Get a decent one person brake bleed kit if you haven’t done so already. Remove the drivers seat when doing the clutch master cylinder. Seems excessive in the beginning but you’ll thank yourself later. (Assuming B3 clutch master cylinder is up with the pedal box). __________________ 1985 WR quattro, 1985 20vT RallyRep, 1993 MTM ABY S2 Avant. 2010 S3 Sportback.

21-01-22, 10:17 AM	#5
mikes2 4 ring whore! Classic Audi Club Member Join Date: Nov 2007 Location: Polmont Posts: 2,617	In at the deep end there. Not a lot of room to get at the oil pressure sender. There's 2 of them. Lower one is fairly easy and just needs a spanner. Easiest to go in from the engine mount side. The top one, there is a water hose that gets in the way. I use a spanner behind the water hose which you'll need to stretch slightly away from the block and slot it down behind the sensor (17mm) to undo it. You might lose a small amount of oil. I'd recommend a pressure bleeder for doing the brakes and clutch. Bleeding is done in order - longest brake line away from the master cylinder gets done first. Rear left, rear right, left front and right front. Minimum of 250ml of fresh fluid from each caliper. I always do more from the first one. Clutch master is a messy job. Put cloth or towel down in the foot well. Clamp off the hose from the brake fluid reservoir to the clutch. Undo the hydraulic line in the engine bay - you'll need a container to catch the fluid. Note this is an unusual size at 12mm. Inside the car, the hose needs to be pulled off the MC - there's a hose outlet on the top. Based on my experience the fluid will go everywhere. It's held on by 2 bolts which need an allen key to undo. The most difficult part will be re-threading the hydraulic line into the master cylinder. I'd suggest wire brushing the threads of the line to clean them up. It needs to be bolted up inside the car first. You'll then need to bleed the clutch from the slave which is on the gearbox. Turn the steering all the way to the right for better access __________________ 1991 90 quattro 20v sport 1991 90 quattro

21-01-22, 09:58 AM	#3
xxErix Grown up member Join Date: Jun 2015 Location: Leeds Posts: 31	Ive got a mate to help me out, so got two people for bleeding breaks

21-01-22, 10:05 AM	#4
xxErix Grown up member Join Date: Jun 2015 Location: Leeds Posts: 31	Also. Appart from break oil, do i need anything else to bleed them?

21-01-22, 11:20 AM	#6
xxErix Grown up member Join Date: Jun 2015 Location: Leeds Posts: 31	Thank you. Very useful stuff there. Hopefully me and my mate can figure it out. Ive orded all new parts from autodock. So hopefully will all fit.