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MOT booked for Thursday, a bit of guidance needed...

PostPosted: Tue May 03, 2011 11:08 am
by Steve G
Hi Guys

I have just had two weeks off work and got my car up to speed for the MOT which is now booked for Thursday. I have fitted my new three point harnesses (very generously donated to me by Brian Clarke - what a hero) checked all of the lights, fixed the horn, adjusted the handbrake and given it a good road test down to the local petrol station and filled up the 16 litre (!) fuel tank. It was a fantastic drive along the coast road, my adrenaline going the whole time - partly due to the excitement and novelty of driving one of my all time favourite sports cars and partly due to looking out for the police!

I wonder if anyone can give me a bit of guidance as to common things that fail an MOT on an Elan and general things I can try and 'preempt' before the big day on Thursday. I know I have 10 days grace after the test to put right anything for a free re-test but I would like to sort as much as possible beforehand. For instance, my Weber carbs have not been tuned and even though they don't seem to be out by much (no coughing or rough running) could this fail the car on emissions? It is a 1970 S4 DHC by the way.

Re: MOT booked for Thursday, a bit of guidance needed...

PostPosted: Tue May 03, 2011 11:25 am
by rocket
Hi Steve,

Seems you have taken care of obvious common points such as handbrake and electrics.As for emissions they shouldnt be a problem unless you have a visable smoke trail...good luck.

Ian.

Re: MOT booked for Thursday, a bit of guidance needed...

PostPosted: Tue May 03, 2011 11:27 am
by miked
Steve,

A few general suggestions.

Tired/moist flexible brake hoses
Any wetness on brake system pipe joints.
Lower trunnion play
Steering rack -track rod ends and track rod ball play.
Rear wheel bearing play


Mike

Re: MOT booked for Thursday, a bit of guidance needed...

PostPosted: Tue May 03, 2011 3:01 pm
by bast0n
Steve

and filled up the 16 litre (!) fuel tank


You have got a problem if that is it's capacity.........................!!

Re: MOT booked for Thursday, a bit of guidance needed...

PostPosted: Tue May 03, 2011 4:28 pm
by bcmc33
miked wrote:A few general suggestions.

Tired/moist flexible brake hoses
Any wetness on brake system pipe joints.
Lower trunnion play
Steering rack -track rod ends and track rod ball play.
Rear wheel bearing play
Mike

Steve,

Mike pointed out the first couple of things that came into my mind based on my experience with failures and tester comments.
I now grease the steering rack and trunnions the day before an MOT as it temporarily reduces the feel if any play is there.
Last year I had comments that one of the track ends had the start of excessive play - less than 100 miles since both being replaced with new ones. Probably Chinese copies even though bought from a reputable source. So this thread has now reminded me to change them before the next test.

Re: MOT booked for Thursday, a bit of guidance needed...

PostPosted: Tue May 03, 2011 4:34 pm
by terryp
Agree 100% with the lower trunnion play. I also always grease just before taking the car! (I had a Ginetta fail on new trunnions as the chap didn't quite understand what play was acceptable)
Also I adjust the handbrake and adjust the mixture/ balance of the carbs (I beleive any smoke is a possible fail in the UK) post 1973 vehicles here in France have to comply with <4.5% C02!!!
I also had problem with headlamp alignment , but my last tester here said (in French!)........ you don't go out at night do you? I replied ...of course not! and he passed it!
Reversing light bulbs have a knack of vibrating out and the number plate lights have a tendency to lose their connection?

Bon Courage!

Terry

Re: MOT booked for Thursday, a bit of guidance needed...

PostPosted: Tue May 03, 2011 8:22 pm
by Allison
Hi Steve,

all the above are good points - but not ones I've had trouble with! You've not mentioned chassis - front turrets are possible areas to check (but 10 days is probably insufficient to put right). My recent MOT's had silly problems - slow wiper speed/wipers not clearing properly and similarly the indicators not flashing properly. Rear wheel bearing play was mentioned but I suggest that the front bearings are more likely to give trouble - mind you I'm talking S3 where the rear bearings are not adjustable and are either good or useless, don't know about your model.

BTW after our last MOT we had a letter from DVLA querying the chassis number - shows the level of detail they or their computer go to - the tester had put "36/xxxx" whilst the log book just showed "xxxx"

Peter

Re: MOT booked for Thursday, a bit of guidance needed...

PostPosted: Wed May 04, 2011 12:01 am
by bcmc33
Allison wrote:Hi Steve,

all the above are good points - but not ones I've had trouble with! You've not mentioned chassis - front turrets are possible areas to check (but 10 days is probably insufficient to put right). My recent MOT's had silly problems - slow wiper speed/wipers not clearing properly and similarly the indicators not flashing properly. Rear wheel bearing play was mentioned but I suggest that the front bearings are more likely to give trouble - mind you I'm talking S3 where the rear bearings are not adjustable and are either good or useless, don't know about your model.

BTW after our last MOT we had a letter from DVLA querying the chassis number - shows the level of detail they or their computer go to - the tester had put "36/xxxx" whilst the log book just showed "xxxx"

My tester (although a young guy) says no play on the front wheels in an Elan is a definite failure. All taper wheel bearing axles must have some degree of play. So it may be wise to make sure that you have the correct amount of play on both front axles.

A friend had a a tester make an error on the VIN by writing a 6 instead of G, and it took months to resolve with the DVLA - so it is good advice to make sure that the tester gets the VIN correct.

Re: MOT booked for Thursday, a bit of guidance needed...

PostPosted: Thu May 05, 2011 11:37 am
by Steve G
Thank you for all your very informative replies. It just failed but I'm not too disheartened because it only failed on brakes binding (and lack of parking brake effort - surprise surprise). This is probably because the car hasn't been driven properly for well over a year now and the pistons are rusty. The garage are not able to fix them until next Thursday so I'm going to attempt to rebuild the callipers this weekend. I'm going to get a couple of these from fleabay;

http://cgi.ebay.co.uk/CALIPER-REPAIR-KI ... 35b137d043

I helped a friend rebuild his brakes on his BMW 2002 and remember it being a complete pig of a job but the brakes were great afterwards. Getting the pistons back in without a proper tool was one of the hurdles.

I can see the finish line!

Re: MOT booked for Thursday, a bit of guidance needed...

PostPosted: Thu May 05, 2011 12:40 pm
by ken ob
I would have thought that an autograph or free tickets to Anfield would have got you a pass certificate.
You are THAT steve g aren't you? :lol: :lol:

Ken.

Re: MOT booked for Thursday, a bit of guidance needed...

PostPosted: Thu May 05, 2011 12:55 pm
by Steve G
ken ob wrote:I would have thought that an autograph or free tickets to Anfield would have got you a pass certificate.
You are THAT steve g aren't you? :lol: :lol:

Ken.


I'm afraid not Ken, when a football rolls near me in the park, I'm the guy who pretends he hasn't seen it and alters course to avoid the embarrassment of toe punting it 300 yards in the wrong direction. Feet too far away from the eyes you see (although Peter Crouch manages and I'm the same height so no excuse).

Does this VIP leniency phenomenon explain why footballers are always parking their sports cars half way up trees?

Re: MOT booked for Thursday, a bit of guidance needed...

PostPosted: Thu May 05, 2011 3:44 pm
by paddy
If both fronts are binding I would be looking at the master cylinder before stripping the calipers. It is possible that the pedal is not coming back fully, or there is a problem in the master cylinder that is stopping the fluid from returning.

Jack up the front (both wheels off the ground). If the wheels are binding, take one wheel off try to push one of the pads away from the disc to free that side. If the other wheel magically becomes free as a result, then the problem is the master cylinder.

Another test that sometimes works is to push one pad away from the disc, and then do the other one on the same caliper. If the first piston pops back out again, the problem is the master cylinder, not the caliper.

Obviously, if any of the pistons seem to be seized and it more difficult to push the pad back than on the others, suspect that caliper.

Paddy

Re: MOT booked for Thursday, a bit of guidance needed...

PostPosted: Thu May 05, 2011 4:07 pm
by 69S4
I've had MOT advisories on front wheel brake balance for the last two years. You could notice a slight bias to the right when braking gently but it would pull up square on hard braking. I left it to see if it would self cure with more use but last summer it was niggling me to the point where I stripped the calipers down to have a look. The cause was one sticky piston on the near side caliper.

I spent a weekend over it but you could probably do each caliper in about an hour if you had all the bits to hand. Getting the sticky piston out was the only awkward bit and then five mins of bleeding with help from my wife (near side caliper) and son (off side) pushing the pedal. Made a big difference to how the brakes feel and cured the pull to the right.

Re: MOT booked for Thursday, a bit of guidance needed...

PostPosted: Fri May 06, 2011 8:47 am
by Steve G
paddy wrote:If both fronts are binding I would be looking at the master cylinder before stripping the calipers. It is possible that the pedal is not coming back fully, or there is a problem in the master cylinder that is stopping the fluid from returning.

Jack up the front (both wheels off the ground). If the wheels are binding, take one wheel off try to push one of the pads away from the disc to free that side. If the other wheel magically becomes free as a result, then the problem is the master cylinder.

Another test that sometimes works is to push one pad away from the disc, and then do the other one on the same caliper. If the first piston pops back out again, the problem is the master cylinder, not the caliper.

Obviously, if any of the pistons seem to be seized and it more difficult to push the pad back than on the others, suspect that caliper.

Paddy


I think you may be on to something here Paddy, a bit strange that all four brakes failed because of binding and I did just remove the servo and reconnect the brake pipes and refill. The MOT tester said that without inspecting it's impossible to tell if it's seizing pistons or a problem with the hydraulics. I have just bought the kit for the fronts but only ?6 and they will need rebuilding at some point. I will do that test you have described first, thanks for the info.

Interestingly, the MOT tester said he was about to pass the front brakes as they passed the test on the rollers, then when he took it off they binded again, so much that he could not push the car or rotate a wheel, so he had to fail all four (the rears were binding on the rollers).

He was a really nice guy and has said that he knows about the handbrake on the Elans and if I get the brakes to pass he will let the handbrake through! So lucky to find a 'proper' MOT tester on my first one. :lol:

Just a couple of questions;
I did bleed the brakes after refilling but if there was still air in the system would this cause the brakes to bind?

If the test shows that it is the master cylinder, where do I go from there? Does it mean a new master cylinder or repair?

Re: MOT booked for Thursday, a bit of guidance needed...

PostPosted: Fri May 06, 2011 9:34 am
by paddy
From what you've described it sounds very unlikely to be a caliper problem.

Steve G wrote:I did bleed the brakes after refilling but if there was still air in the system would this cause the brakes to bind?


No, if that was the only problem, I don't think they would bind.

Steve G wrote:If the test shows that it is the master cylinder, where do I go from there? Does it mean a new master cylinder or repair?


First I would disconnect the master cylinder pushrod from the pedal and see if the brakes are released. If so, you have a problem with the pedal pivot (not allowing the pedal to return fully), or some other problem that is stopping the pushrod from coming out fully. I had a problem like this where the slot in the clevis wasn't deep enough to allow the pedal to move all the way, and another problem with an adjustable pushrod where the end of the pushrod itself was fouling the pedal and interfering with the movement.

If the brakes are still binding with the pedal disconnected, then the problem is the master cylinder. Pull back the rubber boot, and see if you can see anything from the outside that is preventing the pushrod from coming back fully. You might have some crud under the circlip, for example.

Failing that, it's in the internals of the master cylinder. How new is it? It's not just a worn seal because that would have the opposite effect of what you are seeing. I don't know what would go wrong inside the cylinder with just wear and tear that would give the symptoms. If you want to play it safe, get a new cylinder (but if it was me I would at least want to know the root cause before just blindly replacing it).

Paddy