groaning noise

[FranklinLeicester]

For years now my Marina based Roadster has made a slight noise from the front off side when turning slowly left into a drive or parking space. Recently this has become louder - a dull groaning sound. Way back, I thought it was the rack bearing but the noise persists when the steering is held steady on lock. There is no play in the wheel bearings which I have always checked regularly. MOT found no fault. Wotcher reckon?

[keith_h]

Re: groaning noise

Is it there if you jack the wheel up and spin it on full lock? Are any of thr components near enough to the wheel/tyre to rub on full lock?

(and I have to add the obvious one about the groaning noise when you fill up with petrol, realise you have left your credit cards behind and ask the the other hslf to pay)

[b_caswell]

Re: groaning noise

Is the tyre rubbing on the wing stay?
Or it could be the brake disk rubbing on the edges of the friction area where rust builds up and a little bit of play in the wheel bearing allows the disc to move over under load.
Is it tyre noise? try swapping the front wheels round.
Should have said at Stoneleigh we could have held a clinic.

[FranklinLeicester]

Re: groaning noise

Thanks for your suggestions. There is no danger of anything rubbing although that is exactly what it sounds like. I changed the tyres round about a year ago so it aint that. There is a bit of corruption on the edges of the disc but I would expect that to create more of a scraping metallic noise,but I will scrape it off. And of course it doesn't do it when I am trying to find it. Awkward sod! Thanks anyway, if I find out what it is, I'll let you know.

[macdonald.dm]

Re: groaning noise

Try applying the brake (left foot) while driving slowly left. Should hopefully eliminate brakes as the problem.

[Pierre_Smits]

Re: groaning noise

I also had some groaning noice and mine became worse every day. it started making slow turn to the left. I found out that when I hit the brake the noise was gone.
So, I took both front calipers (L+R) off and cleaned/polished the pistons utill they were shiny again. Do replace the seal and dust covers and if you want you can paint the calipers.
I sand blasted mine and then painted them with heat resistant paint.
When mounting back on the car make sure the bleeding point is at the top. Otherwise you cannot bleed the bakes....I found out the hard way..

I hope this helps?
good luck
Pierre

[FranklinLeicester]

Re: groaning noise

Pierre, thanks for that detailed info and pics. OK, having done the the strip-down etc, what do you think was actually causing the groaning noise?.

[Pierre_Smits]

Re: groaning noise

sorry for the late reply.
You're right, I totally forgot the conclusion part...

The cause of the groaning noise was that the pistons in de brake (caliper) did not go far enough backwards. So, sticky pistons in the caliper was the rootcause in my case. When I took them off I saw a kind of 'ring' on the piston with some rust/dirt This ring had grown over time I think (although the dustcover looked still fine..) and eventually caused the pistons to not go back all the way as they were supposed to (difference is hard to see because they normally do not go much backwards either but probably just a little more: the oly backwards you can see is the relaxation of the braking system)

By the way do not forget to install the brake shoes ...I drove a few kilometers braking only on the pistons and I burned my new dust covers.. One side of the car I totally forgot about the brake shoes the other was installed properly.

The replacement of the inside seals might have helped also in relief of the groaning noise because they might work as a kind of spring to pul the piston back (beside the function of seal). This last part I'm not sure about...

What kind of noise do you hear when you lift the front wheels are off the ground and then start rotating the tires slowely? Before taking the brakes off I heared a very soft screaping noise on the left font wheel.

I've driven about a 20 kilometers with the overhauled brakes and the groaning noise is completely gone :-)

So once more the conclusion:
the sticky or dirty pistons caused the brake shoes NOT to go backwards far enough after releasing the brake. So, the brakeshoe hits the disc a little bit/shallow (?) and in making a turn this becomes noticeable best.

I hope this helps.
Keep me/us updated :-)

[FranklinLeicester]

Re: groaning noise

Ok, I'll go along with that explanation as it is the most likely cause of the problem suggested. As regards spinning a jacked-up wheel, there is a very small amount of friction but that doesn't worry me too much. Since I spoke about the problem on this page I have not had it happen once! I think it happens when the atmosphere is damp or raining. Thanks for your detailed help, it has put my mind at rest and I do not think it is a seroius problem for me at this stage.

[macdonald.dm]

Re: groaning noise

Hi Franklin.

I think what can happen under these circumstances (piston slightly seized in bore) is that the wheel might appear to spin quite freely to begin with, but once you get under way the heat generated by the slight constant friction causes the piston to expand slightly and this can press the pads into tighter contact with the discs.

When I my bought my Berli, I knew one of the front brakes was binding slightly, but the wheel spun ok so I thought I could risk a short run...

2 miles later and I could feel the front 'pulling' towards that side so I made a quick about-turn with smoke beginning to cloud from that arch. A half-mile further on, and complete brake circuit failure as the seals basically burned up...

At the very least, I'd be tempted to jack her up, remove the wheel, and try gently prising the piston back into the calliper. This will indicate whether it's binding slightly, and hopefully will even release it.

As explained by Pierre above, the rubber 'O' ring seal on the piston not only prevents fluid loss, but acts as the 'return spring' for the piston itself. It has just enough 'springiness' to allow the piston to move forward to press the pad against the disc, but the piston doesn't actually 'slip' past the O ring during this movement so the ring 'pulls' the piston back when the brakes are released. The actual 'travel' of the piston is tiny. When the pad wears away a little, the piston then moves further forward when the brakes are applied - enough for it now to 'slip' past the O ring a small amount. Release the brakes, and the rubber O ring pulls the piston back in as before.

[cdow]

Re: groaning noise

I had this exact problem - touching the brake pedal stopped the noise. I put new bearings, calipers, discs and pads on to no avail - that said it hasn't done it so far this year since it's been back on the road.

[FranklinLeicester]

Re: groaning noise

Thanks for this info chaps, I get exactly what you mean and will bear it all in mind. Franklin.