Porsche Enthusiasts Club Forum

Eventually plucked up the courage to take my 1987 2.5 Lux to the MoT place. It failed. Here is the list:

Rusty ferrules on both front brake hoses.
Rear offside brake pipe corroded.
Carbon monoxide emissions excessive.

Advisory's:
Both rear hoses slightly deterioated
Both front brake pipes slightly corroded
Front tyres near the limit.

OK. Can someone advise me how bad changing the brake lines is? Is bleeding the brakes afterwards straightforward? I've changed hoses before on other cars, is there anything to beware of? GSF sell hoses about £15 for the front it looks like...
My big unknown is the rear brake pipe and theemissions. The best they got was 5.22 % when the max is 4.5. HC was 192ppm (max is 1200). Can someone advise the best approach to sort the emissions out? It hasn't been driven for a month or so, but it had a 30mile drive to the test station. Is the brake pipe a big problem?

Any advice and/or idea of what it would cost to sort out is very welcome.

Thanks!

D

Thanks for any advise - if

Front hoses aren't too bad but the pipes will be seized so be organised to change the hard pipe as well as the flexi. I assume they mean the short hard pipe on the rear? In which case it isn't bad as it is only 20 or so inches long. I would do all the flexis in one hit, probably using stainless braided ones, which are not a lot more cash than rubber ones. Whilst doing this do the hard pipes as well do a search here as we've done brake pipes to death recently.
The CO reading could be settings (unlikely given on how bad it is) or the Air Flow Meter (AFM) or less likely the throttle switch. AFM is around 200quid new but try casting for a secondhand one. When I changed mine the car drove hugely better!
Confused by your emissions it should be <3.5% not <4.5%

Brake pipes are not a major job and if you do not fancy it yourself any decent garage can do them for a few hours labour, Emissions......... fire some Redex in the petrol tank and give it a good run some at high revs.
If replacing the rubber flexy brake hoses stick a braided hose kit on negligible cost wise
Should the AFM need replacing Frazerpart are getting good reveiws for refurb on these at a much cheaper price than new.
HTH Jim.

Yep BF Goodrich flexi brake hoses will be under £50 the set from ebay. The rest of the lines should be replaced for around £100. The cars too old for a full emissions test so unless it's burning loads of oil check out your AFM. Euro carparts will get you a new one or else it's Porsheapart in Ramsbottem for a second hand good one. You may need an injector service. (Clean.) Reddex & a good thrash might do it. Sometimes cars fail because they arn't warmed up properly having been left standing in a queue at MOT. Take it yourself & drive it hard for 20 minutes first. Then let it tickover for 3 minutes & test. Theres an adjustment screw on the AFM that may have been messed with. Clarkes garage has a section on testing the AFM. Links on this website.

Thanks for all your swift and helpful replies! I've cleaned and reset the tracking of the AFM and bought a bottle of redex. Is there any way of checking the CO before I get it re-MoT'd? The AFM settings don't look like they've been tampered with. I'm using regular 95RON petrol, does that make any difference? Is there anything else I can do?

I reckon I'll order a set of Hel pipes as they have stainless ends and Goodridge are just mild steel. Just got to decide whether to pay a garage to do the brake pipes or make some myself. . .

If you are making the pipes yourself, I think Screwfix sell the tool to make them. Item number 15190-11 for £ 27.49 including vat should let you make them up. You can buy pipe and connectors on eBay. If you can get the old ones off, it will let you measure them first and make up new ones to match. It should then be a straight swap, as long as you have someone to help you bleed the system. As a child my right thigh was the same as Geoff Capes, bleeding brakes with my dad. As they say " what is the worst that can happen". Please let me know how you get on as I will have to do this in the summer to my 944.

Take the car for a long run, get it up to normal running temperature before getting to the MOT station. Don't ask me why, but I was told that the emissions will improve as the engine gets warmer.

The guy at the MOT place near here did it on mine. Last year the readings weren't great initailly, but the longer the car ran, therefore the warmer it got, the lower the emissions. It was a three mile drive from here, then parked up for ten minutes, then started the engine and did the emissions test. This year it was still three miles, but I parked the car right in the MOT bay and left the engine running for the ten minutes - the results were fine right away.

Also, I think that if you change the oil and air filter it will reduce the emissions. Somebody will be along soon to confirm that either way - take their advice not mine as I'm only putting the theory in other people's heads.

Good luck with it.

I think this is to do with the cat taking time to warm up as they do not work at low temeratures. It is even worse on a cold wet day as the cat is constantly getting sprayed with cold water when driving, so always make sure it is hot by leaving the engine running for as long as possible. I stay with my cars while they are tested, so this is easy to do, but you can imagine some dodgy places selling people new cats because of emission failures.

Even though the S2 has a cat though, it is tested as though it doesn't if it is registered before '92 I think.

No it isn't anything pre-August 92 will have a non-Cat test. Air filter, plugs & oil change will help as John says. Also a good Italian tune up down the local by-pas will blow the muck out & warm it through.
AFM problems are becoming more common now they are getting older, years ago we'd have all been struggling with carbs & settings

Works for non cat cars as well. The westfield will only pass if it has a good thrash & then ticks over for 2 minutes. My '44 has much better readings if treated in the same way. Don't know why this works but it does. For cars with a cat the cat has to lite up so yes your right in that.

had mine MOT'd 2 weeks ago, the tester let the car tick-over until the fan cut in, he then did the emmisions