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I have car power amplifier that is one output blown (long story to explain in detals), and decided when replacing output transistors, also to replace the four electrolythic capacitors (3300uf 50v) in power section (amplifier is about 15 years old, and also was blown as a result of poor grounding so maybe they are bad too). Old capacitors are 24x25mm and were soldered directly (sticked) on the board (so their leads are about 3-4mm) and also were guled with some white plastic glue. New ones that I received are 16x35mm and if I solder them on this way, the cover of the amp could not be holded in place and screwed, they would be 3-4mm higher. In an electronic store they told me to put 3300uf 35v because they would fit, but it would be risky of blowing as I think. Question is, can I solder these new capacitors using their full lenght manufacturing leads and bend them in 90° angle to stay in horisontal position something like this Г (because on the sides that need to be bended there are two metal bridger about 7-8mm high) Thanks alot

I took a demonstration photo, attached on the link below:

https://files.fm/u/pkuraybaa

First, 50V can kill you. Be careful.

Next, for any replacement cap, the allowed voltage would be my first concern. The capacitance value itself would only be in second position in the priority list.

As for the position, we generally minimize their leads length to avoid them picking EMF and other noise (acting as antennas). I know that kind of cap can be expensive, but you can check if it does the job at your satisfaction by "tacking" them rather than by welding them definitively (well, if they don't, you are left with "expensive" cap, which is not optimal, but better than having to un-weld them later).

As for the "glue", it should help to keep them in place AND to avoid outside bridging (by humidity or other means) of the pins. The "glue" should not be electrically conductive.

And if you live in a place where it could become cold, since it is for a car, check that the replacement caps can withstand -40C (or -40F, they both are the same at -40).

Just in case, to be sure, electrolytic caps are (generally) polarized, so they must be welded in the right polarity: the (-) pin of the replacement should be where the (-) pin of the existing cap was.

And once more, don't decrease the allowable voltage to 35V if the original is rated for 50V. Exploding cap makes a nice video for YouTube, but there is a good reason those who do it, keep themselves very, very far away from the cap they intend to blow off.