What pressure should I see in the brake lines ?

[Richard309Sri XU5JA 205GTi 8]

I'm trying to get the 309 SRi** ready for MOT and the brakes were very poor. I could turn the front wheels by hand with the brake on before and the pedal would sink to the floor. I think the cup seals had gone! 

 

I reckon the brakes are more or less the same as the **205 GTI 1.6but with a bit more dead weight at the rear as heavier bigger body. (Im on this forum because the engine is the same as the 205 GTi 1.6 also). 

 

I have got a new master cylinder. I have installed. Because I have it on the drive someone told me an easy way to check the 

brake system is to test the pressures, without driving/don't have a rolling brake tester obviously. I have bled in the test gauges. 

 

So on the front I get with the pedal pressed hard down just under 6 MPa which I find equates to 6 BAR approximately 871 PSI? max.

 

Is this a fair result? I think this is fair ish. Im reading it could be more but I am not sure. 

 

I could bled a bit more I think. Im just adding the photo of the test gauge below. 

 

(I've got a chicken and egg as obviously I cant drive to test brakes until MOT, but no MOT so cant drive on the road to test.

I haven't got trailer to take it to MOT test station. I guess I need to find a local recover with a transporter if I am not sure 

I wouldn't want to use the car on the road and risk anyone else if the brakes are not 100% certain;)

 

But if anyone knows that pressure is looking ok that would help me alot and would be much appreciated. 

 

[welshpug 1,657]

should be seeing a lot more than 6 bar the knee point on the gti rear pressure limiter is at 25 bar!

 

is your servo leaking?

[PhilNW 44]

Are you reading it right ? quick google check says 6 mpa is 60 bar   60 bar is 840 psi approx

 

[Richard309Sri XU5JA 205GTi 8]

thanks  for the replies

 

sorry yes I typed it wrong, I have got 60 bar not 6 bar - typo in a rush. 

 

so 60 bar sounds a bit more like it  /? 

 

 

 

Edited August 2, 2021 by Richard309Sri XU5JA 205GTi

[SRDT 180]

You should have 180x40 rear drums like a 205 1.6 GTI but I don't think it's the same brake limiter.

[PhilNW 44]

With 60 bar and a firm pedal, assuming none of the wheel cylinders/calipers are stuck you should have a fair chance of passing the MO 

 

What else have you checked ? 

[Richard309Sri XU5JA 205GTi 8]

Brilliant thanks Phil 

 

I have checked the front wipers and the jets/pump, work/clear to spray enough wash to wipe the windscreen clean

and that's ok now. I had to rebuild the wiper motor as it had water in it but luckily it's good now and I sealed it with extra seal so no water can get back in it. 

 

Lights incl. indicators seem to be ok. I need to check headlamp aim. 

Yes I need to start doing other tests now/this week. Got stuck on first thing looked at, brakes. 

 

The emissions could be a little tough;can smell a little rich. I will look at the older threads about that as there are so many posts about it, so I should be able to use info. already here to get that done. 

 

 

[Richard309Sri XU5JA 205GTi 8]

On 8/2/2021 at 8:56 AM, SRDT said:

You should have 180x40 rear drums like a 205 1.6 GTI but I don't think it's the same brake limiter.

thanks for the comments(sorry for delay as got stuck at work only doing the PUG part time DIY mechanic on the drive. rain stopped me for ages also)

I'm moving onto bleeding the rear brakes next. I think that size is right - I'll check that just for info. 

 

Ah right - I have got the original limiter from the 309 - kept in just in case.glad I did now  

 

I was told it was the same  - so I ordered the right one for the 1.6i 205 - bosch 0 204 131 045 as pictured 

Had to order from spain only place it was listed. 

 

I could put the old one back I guess -  I'll have a look on the parts cat. see what numbers come up. 

 

I know the 1.9 is different for sure, yes I was told the 1.6 was the same so bought the replacement to use based on that. 

 

I noticed that on the 205gti the angle/fixing placing is different so I thought that was also confirmation it was the same. Yeah the 205 has a fixing where it is flatter to the horizontal. 

 

Any further advice be much appreciated as I want to get the rear brakes now set up for an MOT 

 

I thought the old one was blocked but Ill try it again just in case I need to replace that one back in now. 

 

I guess for the pressure at the back I should get less than the 60 BAR I got for the front? 

 

Original one in front of the box of the new one I got. they are exactly the same measurements for sure as just vernier calipers them both 

 

 

 

Edited August 9, 2021 by Richard309Sri XU5JA 205GTi
typo

[welshpug 1,657]

that's a 1.9/309 type valve pictured, they use one either side located near the fuel tank,  not a 1.6 205 type which sits on the chassis leg behind the battery tray.

[welshpug 1,657]

https://www.ebay.co.uk/itm/373593278251?chn=ps&norover=1&mkevt=1&mkrid=710-134428-41853-0&mkcid=2&itemid=373593278251&targetid=1279039638169&device=c&mktype=pla&googleloc=1007413&poi=&campaignid=12689626768&mkgroupid=122363001813&rlsatarget=pla-1279039638169&abcId=9300529&merchantid=7388964&gclid=CjwKCAjwpMOIBhBAEiwAy5M6YFpBW8biXUW98gAa_pMD2bIv1wi2_aMRjG50EelxjPGSmyHBnusl3BoC7m8QAvD_BwE

 

 

 

thats what the 1.6 part looks like.

 

as I mentioned a few posts above, the knee point of a 205 1.9 pressure limiter is 20 bar, 309 gti is 25 bar, I'm not sure what the 1.6 valve is but they work a little differently.

[Richard309Sri XU5JA 205GTi 8]

thanks welshpug, I need to check this out in more detail than I thought. I will be back in touch tomorrow. 

[SRDT 180]

There is more than one pressure limiter for the 205 1.9 and the 309 GTI, some are used by both.

The 1.6 valve is special as it can detect how much the rear is loaded and change the max pressure accordingly. I think it is using inertia to do that so it needs to be oriented the right way.

[Richard309Sri XU5JA 205GTi 8]

@SRDT Thanks Baptiste    

 

I'm moving back onto work on the rear brakes as soon as possible, have a few things to sort out with them then,     I will do another post on that asap. Thanks again also @Welshpug. 

 

@PhilNW I just double checked the FRONT calipers working ok, on the front - with the front wheels off the ground -

 

- Good news for me** - the discs are ROCK solid with the pedal down and the 60Bar shown. Can't shift it by hand whatsoever with two studs screwed in. Then it turns nicely and free again once the brake pedal is released. Pressure reading goes back to 0. 

 

I attach pics - I am going to replace the pads and the discs of course. It was just to make sure the calipers work ok - the calipers are new as the bleed valves socket threads went bad on the original ones. 

 

Shouldn't do this bad practice but just was too curious about it working so started engine put in gear then pressed brakes - stalled engine easily. It's started to polish the old disc I think. I will get new ones for sure now I know the master cylinder and the calipers are ok. I think I will get even more brake power at the wheel with new pads and discs of course. How long does it take to bed in new pads and disc? 

 

(Ideally I need a rolling road on my drive LoL /I would need to test the actual lock up force I guess to know for certain it will pass the MOT with the wheel and tyre on but think it's looking good - fair like you said. thinking out loud - no more testing I can really do on jacks/on the drive - watching youtube videos of MOT brakes roller test - seems to be needing a certain KG force to pass but I can't get that reading until they do a test or I could trailer/recovery it to a test centre/centre where they have a rolling road for a test by that time I might as well get the MOT anyway I guess. Be better to be in the trade/pro. mechanic might be able to trailer and check on the firms test road - driveway mechanic disadvantages). 

 

It's the girling type caliper anyway same the 205 GTI 1.6 I think. Thought pictures might be interesting to the 205 owners also. Realise the disc are now to be replaced just was not worth ordering until the line pressure ok and the caliper tested ok; which now think are both ok. RH side shown but have checked other side also similar check and result - rock solid turns ok when pedal off again, bit of polishing of the disc after stop when running. 

 

**Unless I have made any cock ups I haven't realised*** I think I'm definitely good to get to work on the back DRUMS and SHOES now with just to sort out the pressure limiter........................

 

***one question is there supposed to be a measured distance of movement of the brake pedal itself? 

I'll check the Haynes.