OK, I have send an email and now I think I should not have send it, here is why. Please tell me what do you think.

I have been applying for jobs for 6 months now. I have been to workshops about CVs, cover letters etc. I have asked my supervisor to check my CV and cover letter before applying few months ago, but I didn't get any job with my previous applications.

Now there is a new postdoc advertised and I don't want to loose it, cause i really like the job.

There is a very respected investigator (i will call him "old supervisor") in my field who was my supervisor's supervisor about 15 years ago, therefore I know him and he helped so much before, basically he is very nice and kind person.
When I had my viva he congratulated me so much and asked about my future plans, so I told him I want to stay here (am international student) and do a postdoc, so he told me if you need any help please don't hesitate to ask me for help, you might need it along the way.
OK till now sounds good, but I didn't ask him yet for any advice, I thought it is not nice to ask him and I should ask my supervisor if I need any help and my supervisor should be able to help me, so I did ask for my supervisor advice on my application and as I mentioned I didn't get the jobs.
what I did is I send an email to the "old supervisor" and told hem I would like advice from him for the next job application, and that I want to find out if I'm doing any mistakes.
Now I think this might hurt my own supervisor ( he is very nice to me and I don't want him to think that I'm not respecting him), they are close and am sure the old supervisor will tell my supervisor that I asked for help.

Do you think what I did is wrong or rude, do you think I should tell my supervisor that I have asked help from the old supervisor? just for information my supervisor is aware that the old supervisor offered help previously ( they are both so nice and I don't want to make any problems or mistakes) please advice , I would really appreciate it , am really feeling so bad about it but, at the same time I think the old supervisor might be able to help more, as he is more experienced. :-(

The reason am so confused on what to do is that am a foreigner and the difference between our culture is so huge, so I can't make clear judgement on what is right or wrong.

Don't worry about it, what you did sounds absolutely fine. I'd mention to your supervisor that you contacted him just to keep him up to date with what you're doing. It's not unusual to tell everyone you know that you're looking for a post-doc and to solicit advice from anyone who has experience with the job market :)

I agree - I think what you have done is absolutely fine. You have formed a small academic and personal connection with this gentleman and you are keeping in touch as he told you to do.

Well done!

I wouldn't worry about it. It's rather normal. If you feel uncomfortable, the next time you see your supervisor, you can tell him that you also contacted the other one for help.

thanks everyone